lightroom classic not starting

Also see a somewhat similar post:

https://community.adobe.com/t5/lightroom-classic-discussions/lightroom-classis-an-widows-11/m-p/14798651

As that post also relates to OneDrive

Oh, good catch by Pat Berntsen, OneDrive.

 Your screenshot of that folder was a bit tight, as such I do not see what drive, and more importantly what folder that is in. I suspect the Windows Pictures Folder. The Pictures Folder, and the Documents Folder, and sometimes the Desktop are all Libraries that OneDrive can/will latch onto.

I overlooked those green check marks and the Blue Cloud icon, I think that means OneDrive.

While one member thinks LrC on OneDrive is match made in Heaven, many other members think that it is Hell. I for one recommend avoiding LrC being mixed up with OneDrive like the Plague.

I would recommend that you create on a hard drive connected to your computer, internal or external, a Folder all alone. Perhaps call it MyPhotos, or Lightroom, or Rumplestiltskin, anything other than Pictures. Then copy the catalog(s) to that folder. I have no idea where your photos are, despite apparent ADOBE support for them being in the cloud (like OneDrive) avoid that and copy/move them as well. You may need to deal with missing folders or photos after that in LrC.

As for that Backup Folder. Remember to keep backups on a separate media from the working files, a different hard drive, and remember to have multiple backups.

https://www.computer-darkroom.com/lr2_find_folder/find-folder.htm

Please use your Windows File Explorer and bring up the folder your Lightroom Catalog is in. And then post in a reply a screenshot of that folders content.