Outlook (Classic): When moving a folder to another folder, why does it either (a) return to the original location, or, (b) duplicate the folder, sometimes with only some of the subfolders and emails transferred over?

Question

I have created a number of folders and subfolders under an Inbox subfolder named Archive. These have been functioning well.

However I would now like to restructure my Outlook email filing system and, under Archive, created some new main heading subfolders to move other subfolders into. However when I attempt to move them, either:

(a) they move and then return to the original location, or,

(b) will move by creating a duplicate file (or file with the same name, with a "(2)" after the name), but often this will result in only some of the files being transferred with it, leaving others in the original file. At other times, it seems to have duplicated the files within the transferred folder (i.e. the original folder and the (2) folder now have (at least some of) the same files).

This has resulted in a mix of duplicated folders and files, some of which are complete, others which are incomplete, including some folders which seem to have completely lost their content in both the original and duplicate. I now have no idea how to sort this mess out - I'm somewhat savvy, but not to an indepth level.

Therefore:

(1) Please could someone explain why Outlook is doing this and how to avoid it for the future, and

(2) Please could someone advise on how to fix this mess.

(NB Unfortunately I do not have a backup of the .pst file - I was running backups but recently reinstalled Windows and forgot to set up my backups again.) :(

Many thanks for your help.

Answer 1

Are you in thread display mode, which can be set on a folder-by-folder basis?
If so, emails of the same thread stored in different folders will also be displayed in the list.

<Japanese>
フォルダ単位で設定出来るスレッド表示の状態になっていませんか？
その場合は、別フォルダに格納されている同一スレッドのメールも一覧に表示されます。

Answer 2

Hi @Benjamin Abbott

Welcome to our forum!

This issue in Outlook (Classic) can be caused by a variety of factors, such as delayed syncing, corrupted data, software errors, and more.

Try the following possible solutions:

Check web access: Log in to your email account through the web interface to see if the folder and its contents are displayed there correctly.

Wait for sync: After you move a folder, give it some time to fully sync before doing anything else.

Check for updates: You can't drag and drop emails to a folder in classic Outlook. This issue was fixed in Windows Update for Windows 11, version 24H2 on February 25, 2025.

Repair Outlook: Use the built-in repair tool to fix any potential corruption in your Outlook data file. Repair an Office application - Microsoft Support

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