What did you copy from the Mac to the PC? The mbox files in the Mail/Local Folders location of the Mac profile, or did you save the messages in Mac Local Folders to eml files?

I saved the actual folders from the Mac Profile. Mail>Local Folders. No conversions. Then I copied these into the Windows Profile in the corresponding location. Restarted TBird, but nothing shows up.

Close TB, open Mail/Local Folders in the profile folder, delete all .msf files, then restart TB and see if the folders appear under Local Folders in the Folder Pane.

Did as you said....went into all the subfolders and deleted the .msf. Reopened TB, but nothing shows up.

Do you still have TB on the Mac? Open TB, select all messages in a Local Folder (Ctrl+A), then Ctrl+S to save them as eml files. Copy the eml files to the PC, create a new folder under Local Folders in TB, then drag the eml files from File Explorer and drop them onto the new folder in TB. Do the messages appear?

I'll try this. It could take some time.....27 GB of emails organized into folders. :)

If your folders were 27GB, it might have taken some time for TB to rebuild the msf files on restart (Tools/Activity Monitor to see the progress), before the folders appeared. Try saving as eml for one small folder to see if it works.

I was thinking the same....do a trial run!

Yes, one small folder does show up on the sidebar. But when I ask it to open in a new tab, the wheel keeps spinning, and nothing appears. I'll leave it overnight to see what happens, but at this point it hardly seems worth it.

OK, I just stumbled on the solution. In the TB left-hand sidebar, recreate each top-level local folder with exactly the same name that it had on the Mac version. As soon as the folder appears, all sub-folders and emails will magically appear. Woo-hoo!!