[Fix] Windows can’t find one of the files in this theme error

At regular intervals, you may see an unprompted “Save a Theme” error message dialog on your Windows 10 computer. When you dismiss the prompt by clicking either “Yes” or “No,” the pop-up may reappear.

Cause

The “Windows can’t find one of the files in this theme” error can occur due to one of the reasons:

• The theme you downloaded is a malformed theme.
• Your current theme is broken. It’s missing a file that was defined at one point (in the .theme file) as being part of it. The missing element in your theme file may be a wallpaper image (.jpg, .jpeg, .bmp, .dib, .tif, .png), sound file (.wav), cursor (.ani, .cur), icon (.ico), or the brand image (.png) file.

The error message is generated by SettingSyncHost.exe — File description: Host Process for Setting Synchronization. If you have enabled syncing Themes, the host process for setting synchronization tries to sync your theme to the Microsoft cloud and then this error occurs.

RELATED: Using the Find Window’s Process feature in Windows Sysinternals Process Explorer, you can find the process that owns a Window or dialog.

[Fix] Windows can’t find one of the files in this theme

It is possible that the theme you’ve downloaded is malformed. The .theme file may have bogus elements inside, pointing to one or more non-existent files. The Windows 10 Settings synchronization tool is notifying you that an item in the theme is missing.

Another possibility is that you customized the theme by adding a screensaver, wallpaper images, sounds or cursors from a different source, and later deleted the theme-related files, renamed or moved the theme assets folder to a different location on the hard drive. Either way, the theme becomes malformed.

Redownload the theme or Switch to a new theme

The best way to fix the problem is to delete the theme you’re using and download a fresh copy from the Microsoft Store. If the error reappears, then the theme pack itself could be the problem. Switching to another theme should help.

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\SettingSync\SyncData\Namespace\windows\theme

Does “Save theme for sharing” option work?

Let’s perform a small test.

• Click Start → Settings → Personalization → Themes
• Right-click on your current theme, and click Save theme for sharing
  

Are you getting the same Windows can’t find… error? If so, you should be able to find out the missing theme elements by repeating the process when running a Process Monitor trace (for advanced users). In Process Monitor, you need to include SettingSyncHost.exe in the filter.

Note: In the upcoming 19H1 Windows 10 feature update v1903, Microsoft will make some changes so that the “Save a Theme” prompt will not appear frequently.

We’ve made some improvements to reduce the number of times where you might see the error “Windows can’t find one of the files in this theme. Do you still want to save the theme?” appear. ~ Src: Windows 10 Insider – Windows Experience Blog.

Workaround for “Save a Theme” error

If reinstalling a theme or switching to a new theme doesn’t help, you may disable syncing of Themes as a workaround.

• Click Start → Settings → Accounts → Sync your settings
• Turn off the toggle switch for Theme
  

Disabling syncing, I agree, is not a permanent solution. But, at least gets rid of the annoying Save a Theme error annoyance.

Here is my post at Microsoft Answers back in 2016. Around 650 users have indicated that this has solved the problem.

The synchronization engine must be designed such that, should there be missing theme elements, it should ignore the missing parts and proceed on to the next file. It’s something the Windows 10 team has to do, and hopefully, they get this issue fixed in the upcoming build 19H1.