Why Windows 7 and Windows Vista Show Up “Unsaved Theme” in Themes Listing in personalization ?

A desktop theme contains various settings such as cursors, icons, wallpaper, screensaver and other UI settings. It’s obvious that when one of those theme parameters is changed, Windows saves the customized setting in a separate theme file named Custom.theme, which is displayed in the Personalization window as "Unsaved Theme".

"Unsaved Theme" Reappears Automatically After Deleting?

If the "Unsaved Theme" is reappearing automatically even after deleting it (which wipes out Custom.theme), it could be a shell enhancement software running in the system and making changes to certain theme parameters (REF: Theme File Format). To know which setting is exactly being modified under the hood, you could do so using a text file compare utility like Compare It!.

1. Start Compare It!

2. Browse to the following location:

%LOCALAPPDATA%\Microsoft\Windows\Themes

3. Select the first .theme file, the theme you were previously using.

4. Select the second .theme file Custom.theme

And here comes the comparison… every change highlighted in green color.

(Fig 5, the SizeAll mouse cursor setting changed by an unknown program.)

Depending upon which theme parameter was changed and the resulting value data, you might have a clue about the program which changed the setting. If not, you may use Process Monitorto investigate this further.