I can save all files (of any file-type/extension, even html) but not the file
index.html once it was opened on localhost (for example via http-serve).

Closing localhost-connection/shutdown local server doesn't change behavior.
Sometimes the error-message is 'error on saving ...', sometimes PsPad runs
directly in a memory error and needs to be restarted.

Opening the file index.html in another text-editor (for example notepad.exe) and
edit/save it doesn't cause any problems, even with localhost serving and/or
opened in PsPad at the same time.

Is there any solution/workaround out?

PSPad freeware editor https://www.pspad.com

Odpovedet emailem