Last Reviewed:  April 19, 2023

After You Open an Outlook MSG File, You Can't Re-Open, Delete, or Rename It


You've saved an Outlook email as an MSG file. If you open then close the file, you can't re-open it, rename it, or delete it in FileCenter. When you try to re-open the MSG file, you get an error message that says, in part:

We can't open [filename]. It's possible the file is already open, or you don't have permission to open it ...

or ...

Can't open file: [filename]. The file may not exist, you may not have permission to open it, or it may be open in another program.

This only happens if Outlook is running, and it goes away if you close Outlook.


Outlook fails to release the message. This isn't normal behavior. Normally Outlook should release the message as soon as you close it. Any number of things could be causing the problem.

Solution #1

The simplest solution is to use FileCenter's Professional's "Preview" button instead of opening the MSG file. The previewer gives a faithful view of the email message without opening it. This is all that you need most of the time. Then if you need to extract an attachment or reply to the email, you can still open it in Outlook.

Solution #2

Often, an add-in is to blame for locking the message. In particular, we've found that Evernote's add-ins will cause this problem. Disabling your add-ins will get things working again:

  1. In Outlook, go to the File tab
  2. Select Options
  3. Select Add-Ins on the left
  4. Near the bottom of the window, you'll see a Manage option; set it to COM Add-Ins and click Go
  5. De-select all of the add-ins and click OK
  6. Restart Outlook

Things should now work normally. You can then go back and start re-enabling the add-ins one by one until you find the one that's causing problems.

Solution #3

One reported problem is a corrupt Outlook "extend.dat" file. The solution is to force Outlook to rebuild the "extend.dat" file, which is fairly easy to do.

IMPORTANT: This is normally a safe operation, but you should still make sure you have your Outlook PST file backed up before you try it.

To rebuild your "extend.dat" file, do the following:

  1. Quit all programs, especially Outlook
  2. Click the Windows "Start" menu and select the "Find" or "Search" option
  3. In the search options, select "All Files and Folders"
  4. In the "Named" or "All or Part of the File Name" box, type extend.dat
  5. In the "Look In" list, make sure your local hard drives are selected
  6. Be sure to select "Include Subfolders"; this may be under the "Advanced" option
  7. Click "Search" or "Find Now"; let the search run until it's finished
  8. In the search results, right-click on each extend.dat that's found and select "Rename" from the pop-up menu; change the name to extend.old

Now restart Outlook to rebuild the "extend.dat" files. Once Outlook starts, you should be able to open and close MSG files repeatedly without getting the error.

Solution #4

Some users have found that the Adobe Acrobat Office add-in can cause this problem. If you are comfortable editing the Registry, the following may fix the issue.

IMPORTANT: Editing the Registry can cause Windows to become unbootable. Edit the Registry at YOUR OWN RISK. We cannot assume any responsibility or liability for anything you do in the Registry or for carrying out the following procedure.

  1. Close Outlook
  2. Open the Windows Registry Editor (you can go to the "Run" option in the Start menu and enter "regedit")
  3. Locate and select "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\Outlook\Addins\PDFMOutlook.PDFMOutlook"
  4. Locate and select the "LoadBehavior" option
  5. Go to the "Edit" menu and select "Modify"
  6. Change the value from 3 to 2
  7. Click OK
  8. Close the Registry Editor
  9. Restart Outlook

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