Can't open files copied from Windows 10 to 11. Quickie solution please!

It seems like the issue you are facing could indeed be related to OneDrive on Windows 11. OneDrive might be syncing the files in a way that prevents them from being opened locally on the PC. However, there are a few potential solutions you can try to resolve this problem:
1. Turn off OneDrive syncing: One option is to temporarily disable OneDrive syncing on the Windows 11 PC. To do this, right-click on the OneDrive icon in the system tray (located in the bottom-right corner of the screen), select "Settings," go to the "Account" tab, and click on "Stop sync." This will prevent any potential conflicts between the cloud-synced files and the local copies.
2. Move the files to a different location: If the files are located within the OneDrive folder (c:\users\jeff\onedrive\documents), try moving them to a different location on the Windows 11 PC, such as the local Documents folder (c:\users\jeff\documents). This way, they won't be subject to the same OneDrive syncing restrictions.
3. Copy the files directly to the local destination: Instead of copying the files using the robocopy command to the OneDrive folder, try copying them directly to the local destination on the Windows 11 PC (e.g., c:\users\jeff\documents). This will avoid any potential conflicts caused by the OneDrive syncing process.
4. Open the files using alternative applications: If the files still cannot be opened after trying the previous solutions, you can try using alternative applications to open them. For example, if you're having trouble opening documents, try using Microsoft Word or another compatible word processor to access the files.
Remember to make backup copies of the files before trying any solution in case something goes wrong. Hopefully, one of these options will allow you to open the copied files on the Windows 11 PC.