"Windows cannot find one of the files in this theme" annoying error

Hello,

Store in my profile works flawlessly..It launches immediately, I see my profile, I can download, and in fact it has just updated some of my apps.

I must admit though that some time in the past, probably 1-2 years ago, it could NOT update some previously purchased apps..it would download new apps but could not update certain apps previously purchased. I had looked into it and it appeared to have an issue with the licence file, despite my profile was always present in the store. I can recall it would start the download, freeze, and then it would display an error (while other apps in the queue would download as per normal). If my memory serves me right, I may had purchased apps from the same profile (my microsoft account, I have only got one) but from different computers, not sure though.

The issue went away after a couple of Windows updates and I haven't spotted any download or updates from Store for quite a number f months.

Thanks a lot

OK, I created a new user account (local account), with administrator rights.

I logged out of my usual account (it's linked to my Microsoft Account), and logged in with the test local account.

Windows Store launched, however I did NOT sign into Store (I thought not to use my Microsoft log-in account), and did not connect to OneDrive.

Went to Themes page, no error. After a few seconds, a number of themes started to download themselves, probably old purchases (they did ring a bell). No error whatsoever.

I thought that these were maybe "missing themes" that my normal profile (where I log-in with my Microsoft account) was trying to "locate", and if it couldn't find them hence the error.

So, I made a copy of all those themes.

I then logged out of my test local account, and back into the usual account with Microsoft account log-in. I pasted all themes into the Theme folder, hoping the error would go away.

But no. The number the error comes has now increased from 15-17 times to about 30 (probably by the number of "new themes" added).

This is really getting interesting..can't figure out what's looking for. The surprising thing was to see themes downloading automatically to the test account theme folder, where I had NOT logged into Stores, and there is no error in the test account after download...

To convert the local test account to a non-local one, it means to log in with a Microsoft account, does it mean having to create ANOTHER Microsoft account, or can I log in to the test account using my existing Microsoft account?

If I am able to log-in to the test account using my existing Microsoft account, is it going to mess the original one?

Oh, I should also say I went back to the original themes folder in the original profile (Microsoft account), removed all folders apart of the default Microsoft ones, and I am now again down to the error going down to 17-18 times from the 30-32 I had when I brought all "missing" themes in the themes folder of the original account

OK, so:

1) I de-synced again Theme sync while in original microsoft account; still got errors

2) I then re-visited Option 2 from de and re-registering Apps; I have done for Store and Settings. No red fonts in either re-registering, completed fine; Still got errors (original Microsoft account)

3) Removed Internet (in original account), still got errors

4) Logged back into test account -local -where I had no errors; logged in OneDrive using my Microsoft account, still no errors

5) While in test account -local-, I logged into Microsoft Store; logged me in, and at that time Windows changed automatically my sign-in from local password to using my Microsoft account; no errors (I don't think though it changed the account form itself); stayed there for 30 mins just in case, no errors

6) Logged back to original Microsoft account, still getting errors; while in the original Microsoft account, I checked the status of the test account, it appears as "local"; note that when I logged-in the test account after it let me sign-in with the Microsoft account password, the "local" account also activated Windows Hello (I had to block my Windows Hello sign-in camera in order to let me choose in which account I want to log in).

Buffling eh? !!

Many thanks!
Christos