Microsoft Outlook out of memory or system resources close some windows or programs and try again

Q: What do you do when Outlook is hanging while opening mail memory errors?

Outlook Not Responding error - working solutions for hanging, freezing and crashing problems.

I've got a fair amount of Personal Folder (pst-files) connected in Outlook and I wanted to add another one. When I tried, I got the following error;

Inhaltsverzeichnis Show

Solution 1: Decrease the amount of pst-files that you have open in Outlook
Solution 2: Decrease the memory cache-size per pst-file via the Registry
Possible Cause
Method 1. Reduce Number of PST Files in MS Outlook
Method 2. Reduce Memory Cache-Size per PST Using Registry
Method 3. Extract Heavy Attachments from MS Outlook
Concluding Thoughts
How do I clear the full memory in Outlook?
How do I allocate more RAM to Microsoft Outlook?
What do you do when Outlook is hanging while opening mail memory errors?
How do I clean up Outlook settings?

"Out of memory or system resources. Close some windows or programs and try again."

My system has lots of memory (4GB) and still plenty of memory free but even after closing all other applications and restarting my computer, I still get the same error.

How can I open more pst-files?

When Outlook connects to a pst-file, it stores and reserves as certain portion of memory as a cache to increase performance. For this, Outlook only has a certain amount of address space available and it is this “memory or system resource” that Outlook has run out on.

To solve this issues there are 2 main solutions;

Decrease the amount of pst-files that you have open in Outlook
Decrease the memory cache-size per pst-file via the Registry

After opening 93 pst-files in Outlook, I was able to reproduce this error...

Outlook 2016, Outlook 2019 and Office 365 show a bit more accurate and helpful error.

Solution 1: Decrease the amount of pst-files that you have open in Outlook

As you will only run into this problem when you have more than 15 pst-files of a considerable size (1GB or more) connected in Outlook or over 50 medium/smaller sized ones (around 300MB), the practical solution would be to decrease the amount of pst-files that you have open in Outlook.

For instance; Disconnect the pst-files that you are not actively using and consider only to archive to a separate pst-file when the work on that specific project or assignment has been completed (which is often a common reason to use separate pst-files).

Note:
If you’ve got less than 15 pst-files connected in Outlook, then the solutions in this article will not solve your issue. In that case, it is much more likely that you’ll fix your issue by running scanpst.exe against all your pst-files, troubleshooting your add-ins or recreating your mail profile. For additional solutions also see; Outlook doesn’t start.

Solution 2: Decrease the memory cache-size per pst-file via the Registry

If there is no way to reduce the amount of pst-file that you need to have connected to Outlook and you are running into this error, then you can reduce the amount of memory cache that Outlook allocates to each connected pst-file via a Registry change;

Key: HKEY_CURRENT_USER\Software\Microsoft\Office\<version>\Outlook\PST
Value name: UseLegacyCacheSize
Value type: REG_DWORD
Value: 1

Note: After applying this Registry change, Outlook’s performance will decrease as fewer read/write operations will now be cached.

MS Outlook

Sherry James ~ Published: May 19, 2015 ~ 3 Minutes Reading

While trying to download the email messages from POP3 Server to PST folder, one of the user gets the following error.

Sending and Receiving reported error (0x8007000E): Out of memory or system resources. Close some windows or programs and try again.

Possible Cause

The reason of getting the “out of memory or system resource” error is you are trying to download more messages that your system can process.

Another reason is Outlook allocates more memory for caching PST files to increase the performance but this will reduce the number of PST that can be opened at one time.

According to Microsoft article a computer with 64 megabytes (MB) of RAM runs out of resources and give this error after downloading max of 1,200 messages (approx.).

Solution

You can try out two solution in order to resolve the out of memory or system resource error.

Reduce the number of PST file.
Reduce memory cache-size for PST file using Regedit.
Extract attachments from Outlook and delete unnecessary emails

Method 1. Reduce Number of PST Files in MS Outlook

You can disconnect PST files which are not used actively from Outlook. This will reduce the number of PST file and remove the Outlook failed to add the personal store to the session and out of memory or system resource error. Also it is recommended to not to open so many PST files as this will slow down the performance of Outlook and consume unnecessary resources.

Method 2. Reduce Memory Cache-Size per PST Using Registry

The alternative solution for the Out of Memory or System Resources Outlook 2010 PST error is to change registry settings. Below are steps that you can follow in order to reduce memory cache-size per PST.

Step 1: Backup your Registry settings first.

Step 2: Open Registry and locate the following key

HKEY_CURRENT_USER\Software\Microsoft\Office\<version>\Outlook\Preferences

Value name: ShowBCC
Value type: REG_DWORD
Value: 1

Note: By reducing the cache-size per PST, Outlook performance will decrease.

Method 3. Extract Heavy Attachments from MS Outlook

Having heavy attachments integrated with Outlook emails makes the application out of memory and darn slow. Due to these large sized attachments, Outlook mailbox exceeds its defined size limit and takes too long to load. Despite this, it becomes sluggish when it comes to send or receive emails; in short it takes a lot of time to perform all operations. Hence, it is recommended to extract attachments from Outlook emails and delete all the unnecessary emails to make free space free in email client. Doing this will resolve Out of Memory or System Resources Outlook error in a few simple clicks even without any hassle.

Concluding Thoughts

Microsoft Outlook is an eminent email client used to send, receive, and manage emails and other data items. But, over time users receive and send so many emails, which makes their Outlook Out of Memory or System Resources. Therefore, this article discloses some simple techniques to fix Out of Memory or System Resources Outlook 2016/ 2013/ 2010/ 2007/ 2003 error prompt.

How do I clear the full memory in Outlook?

Luckily, Microsoft provides a Mailbox Cleanup tool in Outlook that makes it easy to cut down on the amount of email you've accumulated. You can find it by navigating to File > Tools > Mailbox Cleanup. Once you're in Mailbox Cleanup you will be able to: Archive items by using AutoArchive.