Save a Theme error message on windows 10

Solution 1:

As per the Cannot find and save a theme error in Windows 10 after update post, I put some potential solutions together with a bit more detail plus another idea.

Itemized Potential Solutions

Note: Try any of these individually in no specific order.

1. From Settings -> Personalization -> Themes you can first simply try to first change whatever theme you have set when the problem occurs to a different theme, and then change it back to the theme you had set—see if that resolves.

   

2. From Settings -> Personalization -> Themes change your current theme to a different theme and then go to %windir%\Resources\Themes or %localappdata%\Microsoft\Windows\Themes or %appdata%\Microsoft\Windows\Themes and delete the theme (and correlated folder name too if applicable) you had set when the message popped up.

   If you have trouble deleting either, you may need to take ownership accordingly and then delete them after you complete that procedure.

   

   Afterwards from Settings -> Personalization -> Themes -> click on Get more themes in Microsoft Store and download the theme you deleted and then set your theme back to it again—see if that resolves.

   Note: If your problem theme did not come from the Microsoft Store, simply download it again from where ever you got it from instead, and then set it as your theme again. Consider using a theme from the Microsoft Store though if possible.

   

3. If the Background is set to a Slideshow you can go to Settings -> Personalization -> Background, and change the Background drop down to a Picture—see if that resolves.

   

4. From Settings -> Accounts -> Sync your settings, toggle the Sync settings option off and wait a few and then toggle it back on. If that option is not able to be toggled for some reason and grayed out, then in the Individual sync settings, toggle the Theme option off, wait a few and then toggle it back on—see if that resolves.

   

Solution 2:

It looks as though that window comes from SettingSyncHost.exe. I have the same problem, and it appears as though it is related to syncing your theme across machines.

If you go to START, and type Sync your settings you can disable the syncing of your theme. This resolved the problem on my machine.

Although it doesn't explain the root cause, it does seem to solve the problem.

Solution 3:

This message means just what it says - a file is missing from your theme. The error will be detected while syncing, but disabling sync only hides the problem and does not fix it.

As you say that "out of nowhere it pops up", this might relate to the screen-saver popping up after a period of inactivity. Try setting your screen-saver to "None" to see if the error disappears. If it does, re-install or choose another screen-saver.

Otherwise, consider refreshing the theme starting with completely deleting it either using PC Settings for the current user :

Or, if that does not work, then delete through File Explorer for all users :

You might need to Change the owner of the .theme file :

_{(source: tenforums.com)}

Or to Change the permissions of the .theme file you want to delete :

After deletion, re-download the theme, even if it is from Microsoft, and re-install. If the error message returns, then the theme itself is broken and you should choose another.