OneDrive has a feature called ‘files on demand’. This will upload your file to Microsoft’s servers, then delete it locally. Because of this, Windows cannot generate the thumbnails.
- Right click OneDrive in the taskbar
- Click ‘more’ and then settings.
- At the bottom, if ‘save space and download files’ is checked, that is you problem.
If you uncheck it, you will see thumbnails again but OneDrive will re-download all files in the folder.
If it isn’t checked, try clearing thumbnail cache.
- Click the start menu and search for ‘disk cleanup’ and click it
- Select your C: drive and click OK.
- Only select ‘thumbnails’ from the checkbox list.
- Click OK and then Delete.
if neither of those work, I’m not entirely sure what could be the problem. Hope this helps.