1. Edit Huge Files in Fast View Mode

In v26.3, we introduced Fast View mode, which opens a huge file almost instantly without loading the whole file into memory. Fast View mode was read-only, so to edit a huge file, you still had to switch to the normal mode and wait for the whole file to load.

In this version, Fast View mode supports editing. You can edit a huge file without loading it into memory: you can type, paste, Undo and Redo, Replace All, use multiple selections, and run most commands on the Insert, Convert, and Sort menus. The original file does not change until you save it.

1-1. Merge the Edits, or Save Only the Changes

When you save a huge file in Fast View mode, you can choose how to save it:

• Save and merge writes the edits into the file.
• Save only the changes to a diff file leaves the original file untouched and saves your edits in a separate diff file. The next time you open the file, EmEditor loads the diff file and restores your edits.

The diff file also keeps the positions of the lines, so the file opens instantly the next time. You can save, load, and discard diff files with the new Save Diff, Load Diff, and Discard Diff commands (File > Diff submenu of the All Commands menu).

1-2. CSV Editing, Workspaces, and the FAST Indicator

• Fast View mode now supports the CSV commands that change the document, including cell editing, Split Column, Combine Columns, Combine Lines, Hide Quotes Temporarily, Hide/Unhide Columns, Reset Column Width, and Align Left/Center/Right (Pro version only).
• Fast View documents are now included in workspaces, including their unsaved edits.
• The new FAST indicator on the status bar and a lightning bolt icon on the document tab show that a document is in Fast View mode. Double-click the indicator to switch between the normal mode and Fast View mode.

We also added the Fast View page to the Customize dialog box. The Minimum file size to enable Fast View mode setting has moved to this page from the Advanced page, and you can choose whether to prompt when saving a huge file, whether to save only the changes to a diff file, and whether to save the line positions of huge files. The page also lists the diff files so you can delete them.

1-3. Macros and Plug-ins

Most properties and methods of the Document and Selection objects that change the document can now be used in Fast View mode, and we added the GetFastViewDiffPath method to the Editor object. For plug-in developers, most messages that change the document can now be used in Fast View mode, and we added the EI_GET_FAST_VIEW_DIFF_PATH parameter to the EE_INFO message and new command IDs for the diff commands and the Customize Fast View command.

1-4. Command Line Options

We added the /fast and /tail command line options. /fast opens a file in Fast View mode even if the file is smaller than the Minimum file size to enable Fast View mode, and /tail opens a file in Fast View mode and displays the end of the file immediately. /tail is equivalent to /fast /l -1, and we believe it is useful for quickly viewing the last part of a very large file, such as a log file. If you select Auto-Reload from the Changed by another program drop-down list on the File page of the configuration properties, the file is reloaded automatically whenever another program changes it, and EmEditor scrolls to the end of the file, which is useful for monitoring a log file that is still being written.

2. Faster

EmEditor starts faster in this version, and many operations on huge files are also much faster, especially in Fast View mode. In our tests, the main window was ready 1.93 times faster than in v26.3. With a 48 GB file on a PC with 16 GB of memory, Replace All became about 5 times faster and saving the file about 13 times faster, and opening the file the second time took only 0.02 seconds thanks to the line positions saved in the diff file. Sort and Delete Duplicate Lines in the normal mode also became about 6 times and 3 times faster.

3. 31% Smaller Files

In this version, we reviewed the code and the libraries of EmEditor and its plug-ins and made almost every EXE and DLL file smaller. We measured the speed before and after each change and kept only the changes that did not slow EmEditor down in our tests. EmEditor.exe is 57% smaller, and the plug-ins are about 50% to 75% smaller. pcre.dll, zlib1.dll, vccorlib140.dll, and msvcp140.dll are no longer installed. In total, the EXE and DLL files are 31% smaller (69,962 KB to 48,431 KB in the portable version). Smaller files load faster, which also contributes to the faster startup.

4. Other Improvements

• The Start window now supports the App theme and Very dark themes.
• Macros are now saved as UTF-8 with a signature (BOM) instead of UTF-16.
• Synchronization with a sync folder is now faster and more reliable: EmEditor no longer sends settings that did not change, no longer overwrites newer settings that another computer sent, and does not wait when the folder cannot be reached. Synchronizing settings through a Microsoft account is no longer available, because Windows 11 no longer syncs the roaming folder of Store apps between computers. If you used it, please use a sync folder instead.
• Workspaces are now saved and loaded more safely. A failed save no longer destroys the previous workspace, a broken workspace or a workspace saved by a newer version is no longer cleared, and a workspace with more than one window is now saved correctly.
• We added the emeditor /register and emeditor /unregister command-line options for per-machine registration, which lets all users of the same PC use the same license (Pro version only). The Registration Information dialog box now displays the email address of a per-machine registration.
• The Chat with AI bar now opens on the left side by default.
• Store and MSIX versions: EmEditor now offers to remove the file associations left by an uninstalled MSI version, which prevented Windows from opening those files with EmEditor.
• We fixed several problems, including a crash with multiple selections whose carets are out of order, a crash when displaying a line with a very large number of combining characters, and an empty line lost by Sort and Delete Duplicate Lines after a line that ends with CR alone.

5. Security Update

This version addresses the eMudhra Intermediate CA Compromise, a critical security issue. Node.js, which is bundled for the Language Server Protocol feature, was affected, so we updated it to v26.12.1. We scanned the EmEditor source code and found no other affected area: EmEditor uses the Windows CA certificates, and the WebPreview and ChatAI plug-ins use the Microsoft Edge installed on your PC. We recommend keeping Windows and your web browser up to date.

We hope you will be satisfied with both the Pro and Free versions. If you have any questions, feature requests, or ideas, please contact us.

Thank you for your continued support of EmEditor.
— Yutaka Emura

For more details, including the main changes and screenshots, please see “New in Version 26.4”.

If you use the legacy MSI installer, select Help > Check for Updates to update EmEditor. If the update does not complete successfully, please download the latest version and run the installer manually. If you download the MSI installer directly, please verify that its digital signature is issued by Emurasoft, Inc.

The Microsoft Store version is expected to be available within the next few days. We recommend using the Microsoft Store version or the new MSIX installer. The Update Checker of the legacy MSI version is retired after March 31, 2027 (UTC). After that date, EmEditor no longer checks for updates, and Check for Updates is unavailable. For more information, see FAQ: Store Version and New Installer (MSIX).

If we release minor updates (v26.4.x) in the future, this blog post may be updated to include those changes.

1. Fast View Mode for Huge Files

EmEditor has long been known as a text editor that can open huge files, and we have improved the performance of opening and editing large files in almost every version. However, when a file is much larger than the physical memory of your PC, opening the whole file still takes time, and the PC may slow down because of a memory shortage. In many cases, you open a huge file such as a log file or a database dump only to view, find, or filter it, and you do not need to edit it.

In this version, we added the new Fast View mode for such cases. Fast View opens a huge file almost instantly in read-only mode without loading the whole file into memory. EmEditor finds the positions of the lines in the background and reads only the lines that are displayed. You can jump to the end of the document immediately after you start opening the file, even while EmEditor is still finding the positions of the lines. Line numbers are not displayed until the positions of the lines are found.

Files larger than the Minimum file size to enable Fast View mode (4,096 MB by default) are opened in Fast View mode automatically, and a notification appears when a file is opened in Fast View mode. You can change this size on the Advanced page of the Customize dialog box. To switch between the normal mode and Fast View mode, select Fast View on the Edit menu. You can also select the Fast View mode check box in the Large File Controller.

1-1. What You Can Do in Fast View Mode

Although Fast View mode is read-only, most of the features you need for viewing and analyzing huge files are available.

• Both the Pro and Free versions
  • Scroll, select (including vertical selection), copy (including Copy in Quotes), Jump, and Tag Jump.
  • Display highlighted strings, comments, quoted strings, markers, marks, and the ruler.
  • Find text, including regular expressions, the Number range and Fuzzy options, and counting the matches.
  • Reload in a different encoding, including binary views, and Save As with a different encoding or newline characters.
  • Compare documents, including with a document in the normal mode.
  • Run external tools.
• Pro version only
  • Extract with the Find dialog box, Multi-Find with the Batch Find dialog box, and filter and extract with the Filter toolbar.
  • Use CSV modes, the Large File Controller, macros, plug-ins, and the AI menu.

Note that in Fast View mode, the number of bookmarks is limited to 100,000 per document, and the Incremental search options are disabled.

1-2. Much Faster, Even When the File Is Larger Than Physical Memory

Opening, finding, filtering, and extracting in a huge file are much faster in Fast View mode than in the previous version, even when the file is much larger than the physical memory. In our tests, filtering became about 9 times faster, and extracting became more than 10 times faster than in v26.2. If you often work with huge log files or CSV files, please try Fast View mode.

1-3. Macros and Plug-ins

Macros and plug-ins can also be used in Fast View mode. The properties and methods of the Document and Selection objects that do not change the document can now be used in Fast View mode, and we added the FastView property to the Document object. For plug-in developers, we added the EI_GET_FAST_VIEW parameter to the EE_INFO message and the EEID_FAST_VIEW command ID. Properties, methods, and messages that change the document fail in Fast View mode.

We also added the Text and TextLength properties to the Document object, and the scrollBy and scrollTo methods and the scrollX and scrollY properties to the WebBar object.

2. Enhanced Chat with AI

2-1. MCP Connectors

In this version, Makoto Emura added MCP connectors to the Chat with AI plug-in. MCP (Model Context Protocol) is a standard protocol that connects AI to external services. By adding MCP connectors, the AI can access external services and data while chatting with you. You can add new connectors on the new MCP Connectors page of the Settings dialog box using the JSON configuration of an MCP server. Currently, only HTTP servers are supported (STDIO and SSE connections are not supported).

Makoto also added the EmEditor Help Pages MCP connector. When you ask the AI about how to use EmEditor, the AI can use this connector to access up-to-date EmEditor help pages. We found that this MCP gives better answers than web search tools.

One example of a complex task that AI used to struggle with is writing EmEditor macros, such as “Write an EmEditor macro to find the sum of values in column 2.” With the EmEditor Help Pages MCP connector, AI can now reference the macro help pages to write better macros.

EmEditor Help Pages MCP is also available to use in other apps such as ChatGPT or Claude. See this article which explains how to use this MCP server in other apps.

2-2. Per-Chat AI Settings

Previously, AI settings such as the provider and model were shared by all chats. In this version, you can change the AI settings for each chat. Per-chat settings apply only to that chat, and changing them does not affect the global settings. For example, you can use a lightweight model in one chat and a reasoning model in another.

Makoto also added an AI model and tools indicator to the chat input box. It shows the current AI model and the selected tools for the chat, and clicking the model name opens the Settings dialog box.

2-3. The ChatAI Plug-in Is Required

Please note that to use the AI features, including Chat with AI, you need to install the ChatAI plug-in in addition to EmEditor. The Store version and the new Installer version (MSIX) include the ChatAI plug-in, so there is no need to install it separately.

3. Other Improvements

The Explorer plug-in now uses the dialog box font size specified on the Window page of the Customize dialog box.

We hope you will be satisfied with both the Pro and Free versions. If you have any questions, feature requests, or ideas, please contact us.

Thank you for your continued support of EmEditor.
— Yutaka Emura

For more details, including the main changes and screenshots, please see “New in Version 26.3”.

If you use the legacy MSI installer, select Help > Check for Updates to update EmEditor. If the update does not complete successfully, please download the latest version and run the installer manually. If you download the MSI installer directly, please verify that its digital signature is issued by Emurasoft, Inc.

The Microsoft Store version is expected to be available within the next few days. We recommend using the Microsoft Store version or the new MSIX installer. Updates for the legacy MSI installer are currently scheduled to end in March 2027. For more information, see FAQ: Store Version and New Installer (MSIX).

If you uninstall the old MSI version and install the Store version or the new MSIX version, “Edit in EmEditor” may appear twice in the context menu when you right-click in File Explorer. In this case, the new Store/MSIX version will show a dialog box to prompt you to remove the old entry.

If we release minor updates (v26.3.x) in the future, this blog post may be updated to include those changes.

• Fixed an issue where folders added to Favorites did not work correctly.
• Improved performance when a network folder is specified in Favorites.
• Fixed an issue where vertical lines could display incorrectly in Markdown Design View.
• Fixed an issue where the GUID used by the Windows 11 modern context menu conflicted with another app.
• Improved the workspace restoration behavior.
• Fixed an issue with the message box displayed before subscription renewal.
• Fixed various crashes, including one that could occur when saving extremely long lines.
• AI features are now disabled if the version of the ChatAI plug-in does not match the version of EmEditor.
  Note: If the AI features stop working, open Plug-ins > Plug-in Settings and verify that the ChatAI plug-in version is 26.2.9. If it is a different version, reinstall the ChatAI plug-in.

If you use the legacy MSI installer, select Help > Check for Updates to update EmEditor. If the update does not complete successfully, please download the latest version and run the installer manually. If you download the MSI installer directly, please verify that its digital signature is issued by Emurasoft, Inc.

We recommend using the Microsoft Store version or the new MSIX installer. Updates for the legacy MSI installer are currently scheduled to end in March 2027. For more information, see FAQ: Store Version and New Installer (MSIX).

• Fixed an issue where the Add button in the Customize Plug-Ins was always disabled.
• Fixed various crashes, including crashes that could occur while saving a file after out-of-memory errors.

If you use the legacy MSI installer, select Help > Check for Updates to update EmEditor. If the update does not complete successfully, please download the latest version and run the installer manually. If you download the MSI installer directly, please verify that its digital signature is issued by Emurasoft, Inc.

We recommend using the Microsoft Store version or the new MSIX installer. Updates for the legacy MSI installer are currently scheduled to end in March 2027. For more information, see FAQ: Store Version and New Installer (MSIX).

• Fixed an issue that caused the Binary (Hexadecimal View) to appear blank when DirectWrite was enabled.
• Fixed various crashes, including crashes that could occur with the Explorer plug-in.

If you use the legacy MSI installer, select Help > Check for Updates to update EmEditor. If the update does not complete successfully, please download the latest version and run the installer manually. If you download the MSI installer directly, please verify that its digital signature is issued by Emurasoft, Inc.

We recommend using the Microsoft Store version or the new MSIX installer. Updates for the legacy MSI installer are currently scheduled to end in March 2027. For more information, see FAQ: Store Version and New Installer (MSIX).

• Removed the Associate with EmEditor button from the File page of the Customize dialog in the Microsoft Store and MSIX versions.
• Fixed an issue where the status bar did not display Help messages when menu commands were selected.
• Improved the message shown when EmEditor crashes because of an ATOK-related issue.
• Improved the performance of the WordComplete plug-in.
• Improved syntax coloring performance when files contain very long lines.
• Fixed various crashes, including crashes that could occur in low-memory situations.

If you use the legacy MSI installer, select Help > Check for Updates to update EmEditor. If the update does not complete successfully, please download the latest version and run the installer manually. If you download the MSI installer directly, please verify that its digital signature is issued by Emurasoft, Inc.

We recommend using the Microsoft Store version or the new MSIX installer. Updates for the legacy MSI installer are currently scheduled to end in March 2027. For more information, see FAQ: Store Version and New Installer (MSIX).

• Fixed an issue with the Open command when document tabs are disabled.
• Fixed an issue where automatic updates for the Microsoft Store and MSIX versions did not work while the tray icon was running.
• Fixed a potential crash after changing options on the History page of the Customize dialog box.
• Fixed some UI elements related to Dark Mode.

If you use the legacy MSI installer, select Help > Check for Updates to update EmEditor. If the update does not complete successfully, please download the latest version and run the installer manually.

The Microsoft Store version is expected to be available within the next few days. If you download the MSI installer directly, please verify that its digital signature is issued by Emurasoft, Inc.

We recommend using the Microsoft Store version or the new MSIX installer. Updates for the legacy MSI installer are currently scheduled to end in March 2027. For more information, see FAQ: Store Version and New Installer (MSIX).

• Fixed a potential crash when opening multiple files simultaneously.
• Fixed an issue introduced in v26.2.1 where it might not be possible to send an entire very large document to an external tool’s standard input.
• To reduce download and installation failures, the Store and MSIX editions no longer include local Help in the package, consistent with other editions. If you need local Help, please download and install the separate Local Help installer.
• Fixed the icon background color for the Store and MSIX editions.
• Fixed some UI issues related to Dark Mode.

If you use the legacy MSI installer, select Help > Check for Updates to update EmEditor. If the update does not complete successfully, please download the latest version and run the installer manually.

The Microsoft Store version is expected to be available within the next few days. If you download the MSI installer directly, please verify that its digital signature is issued by Emurasoft, Inc.

We recommend using the Microsoft Store version or the new MSIX installer. Updates for the legacy MSI installer are currently scheduled to end in March 2027. For more information, see FAQ: Store Version and New Installer (MSIX).

• Fixed an issue that could cause the wrap mode to change to No Wrap after opening a file.
• Fixed a potential crash when starting EmEditor while checking for conflicts with other versions.
• Fixed an issue with Markdown/HTML style updates.

If you use the legacy MSI installer, select Help > Check for Updates to update EmEditor. If the update does not complete successfully, please download the latest version and run the installer manually.

The Microsoft Store version is expected to be available within the next few days. If you download the MSI installer directly, please verify that its digital signature is issued by Emurasoft, Inc.

We recommend using the Microsoft Store version or the new MSIX installer. Updates for the legacy MSI installer are currently scheduled to end in March 2027. For more information, see FAQ: Store Version and New Installer (MSIX).

• Fixed a possible crash immediately after opening a file.
• Fixed the opening dialog in Store and MSIX versions.

If you use the Desktop Installer edition, select Help > Check for Updates to update EmEditor. If the update does not work, please download the latest version and run the installer manually.

The Microsoft Store version is expected to become available within the next few days. If you download the MSI file directly, please verify that its digital signature is signed by Emurasoft, Inc.