Lightroom Previews Missing After OneDrive Sync — Unable to Rebuild Previews

I opened lightroom and all previews that were present and working properly a few weeks prior were gone. A Onedrive notification shows lots of lightroom files (not the photos themselves) had been deleted. Now I'm unable to successfully run the build standard size previews command on any folder over 10 images or so. Deleting the previews.lrdata folder (as suggested in various other help topics) doesn't prompt the previews to generate or allow the command to work. Signing out and back in to creative cloud doesn't help.

I know I need to get Onedrive out of my workflow but some way to see thumbnails without going through 18,000 images in batches of 10 would be appreciated.