Outlook cannot display the folder, out of memory or system resources: how to fix it

Applies to: classic Outlook for Windows (Microsoft 365, 2021, 2019, 2016 and older). The new Outlook is a different app and doesn’t use the components behind this error.

What the error actually means

When you click a folder, you may see Cannot display the folder followed by Out of memory or system resources or There is not enough free memory to run this program. Both point at the same thing: Outlook keeps a fixed block of shared memory for tracking folders and changes in them, and that block has run out.

Microsoft names two things that use it up: custom folder views, such as a filter, and add-ins that watch many folders across all the mailboxes and data files in your profile. Lots of folders and items make it worse, and so does caching big shared mailboxes. That is why adding RAM or closing your browser usually changes nothing.

1. Reset the folder’s view

If only one folder fails, a filter or custom view on it may be the trigger. Open a folder that works, then select the problem folder again. If it opens, go to View > Change View and choose Compact or Single, then View > Reset View to clear filters and custom columns.

If the folder won’t open at all, close Outlook and start it with outlook.exe /cleanviews in the Run box (Win + R). This resets every custom view to its default, so you’ll lose saved column layouts.

2. Test without add-ins

Close Outlook, press Win + R, type outlook.exe /safe and press Enter. Safe mode starts Outlook with add-ins turned off. If the folder opens there, an add-in is responsible.

1. In normal Outlook, go to File > Options > Add-ins.
2. Next to Manage, choose COM Add-ins and click Go.
3. Clear the boxes for add-ins you don’t need, click OK and restart Outlook.
4. Turn them back on one at a time to find the one that causes the error, then update or remove it.

3. Stop caching shared folders

In Cached Exchange Mode, Outlook downloads every shared mailbox and shared folder you open into your local data file. With several large shared mailboxes, that means many more folders for Outlook to track.

1. Go to File > Account Settings > Account Settings, select your Exchange or Microsoft 365 account and click Change.
2. Click More Settings and open the Advanced tab.
3. Clear Download shared folders. On older versions with public folders, also clear Download Public Folder Favorites.
4. Click OK, finish the wizard and restart Outlook.

Shared folders then open straight from the server. They can feel slower, but they no longer count against Outlook’s local memory. Microsoft also documents a public folder version of this error: Outlook 2010 and 2013 in cached mode with more than about 1,000 public folder favorites.

4. Split very large folders and data files

Outlook has no hard limit on folder size, but Microsoft says performance drops as you approach about 100,000 items in one mail folder, 10,000 in a calendar folder, or 10,000 folders in a mailbox. Problems can also start above about 500 cached shared folders. Folders that load slowly or fail to display are among the symptoms listed.

• Move older mail from an overloaded folder into subfolders by year.
• Use the online archive or retention policies if your organization provides them, instead of keeping everything in the Inbox.
• Close PST files you no longer need: right-click the file in the folder pane and choose Close.
• On Microsoft 365, reduce Download email for the past in the same account settings to keep less mail on the PC.

Check your data file size under File > Account Settings > Account Settings > Data Files (the Open File Location button shows the file). A full file causes different problems, such as mail that won’t send or can’t be moved, and Microsoft doesn’t list this memory error among them. Raising the size limit isn’t a fix here; Microsoft advises against going above the default 50 GB for performance reasons.

5. Give Outlook more shared memory (registry)

Warning: a wrong registry change can stop Windows or Office from working. Back up the registry first (in Registry Editor, File > Export), and use an administrator account.

Microsoft’s workaround raises the size of Outlook’s shared memory block. Close Outlook first.

1. Press Win + R, type regedit and press Enter.
2. Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Messaging Subsystem.
3. Right-click in the right pane, choose New > DWORD (32-bit) Value and name it SharedMemMaxSize.
4. Double-click it, keep Base on Hexadecimal, type 300000 and click OK.
5. Under the same key, open Applications\Outlook. Create the Applications and Outlook subkeys if they don’t exist, then add the same SharedMemMaxSize value there.
6. Start Outlook and try the folder again.

The base matters: hexadecimal 300000 is 3,145,728 in decimal. If the error comes back, Microsoft says you can raise both values as far as hexadecimal 800000. The same thing can be done from an elevated Command Prompt:

reg add "HKLM\SOFTWARE\Microsoft\Windows Messaging Subsystem" /v SharedMemMaxSize /t REG_DWORD /d 0x300000 /f
reg add "HKLM\SOFTWARE\Microsoft\Windows Messaging Subsystem\Applications\Outlook" /v SharedMemMaxSize /t REG_DWORD /d 0x300000 /f

Microsoft’s article doesn’t cover 32-bit Office on 64-bit Windows. If the change has no effect there, the same key may also need the value under HKLM\SOFTWARE\WOW6432Node\Microsoft\Windows Messaging Subsystem.

6. Repair or rebuild the data file

Damage in the data file is a less common cause, but worth ruling out when one specific folder always fails:

• Microsoft 365, Exchange or Outlook.com accounts: close Outlook, open the folder shown by Open File Location, and rename the .ost file (for example add .old). Outlook downloads a fresh copy from the server. Anything that hadn’t synced yet, such as unsent mail in the Outbox, is lost, so check first.
• PST files (POP, IMAP or archives): close Outlook and run the Inbox Repair Tool, SCANPST.EXE. In Microsoft 365 it’s usually in C:\Program Files\Microsoft Office\root\Office16, or Program Files (x86) for 32-bit Office. Browse to the PST, click Start, then Repair. Run it again until it finds no errors.

If none of this helps, create a new Outlook profile from Control Panel > Mail > Show Profiles > Add and test with only your main account. Our Outlook tips cover other ways to keep a busy mailbox fast.

Related guides

• Outlook tips and tricks
• How to add a shared mailbox in Outlook
• Outlook error 0x800CCC92: how to fix it
• Outlook classic download: how to get it back

Official sources:

• Microsoft Learn: “There is not enough free memory to run this program” error in Outlook
• Microsoft Learn: Outlook performance issues with too many items or folders
• Microsoft Learn: Configure the size limit for PST and OST files