[Users] Duplicated sub-folders after Rebuild-Folder-Tree

[Ralph]

Hello!

Windows 10 + 3.17.4 (64-bit)

I've used claws on linux for decade+ but this is a first on windows and
I encountered a weird problem.  After running a Rebuild Folder Tree I
have duplicates of all my mail subfolders in the Folder list along with
duplicates of the subfolder's mail contents.  Structure like this...

Folder1
  Subfolder1
  Subfolder1
 
Folder2
  Subfolder2
    Subfolder2a of Subfolder2
  Subfolder2
    Subfolder2a of Subfolder2

...etc

The folders without subfolders at the top-most level appear normal.

If I delete one of any of the duplicated subfolders and run Rebuild
again, both the duplicate and the original are gone.

This is not good :(  Any ideas?  Thanks.

Ralph