Since installing EmEditor 7 and the EmEditor Sidebar Gadget (have since removed -because this behavior started after it was installed- but still get the error) on Vista (RTM and SP1), each time I attempt to install it tells me that ALL explorer processes must be closed.
If I force quit all explorer processes then the install works fine. If I don’t close all explorer.exe processes then I can not install.
I realize this warning appears, but you can safely ignore this prompt. The file emedshl.dll tries to register to Explorer, but this file does not need to be updated every time. So you can ignore this.