.xlsx files are supported but something went wrong, the file is old on mobile

Hi ThadZab109, thanks for messaging the Community!

Are you viewing the files on the Dropbox app, or on the Excel app after opening it from the Dropbox app?

This will help me determine where the outdated file is appearing?

I open the Dropbox app, select the Excel file and then viewing it using Hancom Office Viewer app.

Clearing the cache has resolved the problem. Thank you. I'm not as tech savvy with tablets and mobile phones as I am with a desktop, so I didn't even think about cache (actually had to Google how to clear cache).

Thanks for the update. Generally, third party apps keep a cache of frequently accessed files in order to speed things up for yourself. 

However, this might result in the app not getting the latest copy of the file, which can lead to this situation. Clearing the cache forces that app to get the latest version of the file.

The second part of my question was the .xlsx files are supported but something went wrong.  Can this occur if the file is password protected?

Hi from me too, ThadZab109! If a file is password-protected, it may throw an error indeed, if you try to preview it. Just to double check though, do you have any other Excel files that aren’t password-protected? If yes, are they throwing this error, as well?

Finally, are your .xlsx files more than 40MB in size?

I have one other xlsx file that does not generate the error and opens without issue.  The password protected file is not even 1MB, so I'm now pretty sure that it's the password that causes the "something went wrong"!