--- description: More often than not, the Outlook error “Out of memory or system resources” usually occurs when you connect too many PST files in considerable size to Outlook. This article will focus on this issue and offer 4 solutions. title: 4 Solutions to Outlook Error “Out of memory or system resources” image: https://www.datanumen.com/blogs/wp-content/uploads/2016/11/Out-of-memory-or-system-resources.png --- - - - [Home](https://www.datanumen.com/blogs/) > [Solutions](https://www.datanumen.com/blogs/category/solutions/) > [Office Solutions](https://www.datanumen.com/blogs/category/solutions/office-solutions/) > [Outlook Solutions](https://www.datanumen.com/blogs/category/solutions/office-solutions/outlook-solutions/) > 4 Solutions to Outlook Error “Out of memory or system resources” # 4 Solutions to Outlook Error “Out of memory or system resources” [Outlook Solutions](https://www.datanumen.com/blogs/category/solutions/office-solutions/outlook-solutions/) September 29, 2025 Share Now: - - - - - - - - *More often than not, the Outlook error “Out of memory or system resources” usually occurs when you connect too many PST files in considerable size to Outlook. This article will focus on this issue and offer 4 solutions.* As a rule, when you open a PST file in Outlook, Outlook will allocate a certain part of memory to it as a cache to improve the performance. In other words, Outlook has a limit in the amount of space available for each email accounts. Thus when the space has run out, the Outlook error “Out of memory or system resources” will turn up. Also, apart from the memory issue, PST corruption is also an important factor. Here are 4 related solutions according to the different causes.![Outlook Error: Out of memory or system resources](https://www.datanumen.com/blogs/wp-content/uploads/2016/11/Out-of-memory-or-system-resources.png "Outlook Error: Out of memory or system resources") ## **Solution 1: Reduce the Number of PST Files Opened in Outlook** From the perspective of the amount of opened PST files in Outlook, there are two types of situations. One is that you are opening over 15 PST files, all of which are in a considerable size of 1 GB or so. The other one is that More than 50 PST files of a smaller size (about 300 MB) are connected in Outlook. If your case is either, the effective method is to reduce the number of PST files opened in Outlook. Therefore, you can close some PST files which are not actively needed. Here you have two available means. 1. In Outlook mail navigation pane, right click the PST files and select “Close” command from the popup context menu.![Close Outlook Files](https://www.datanumen.com/blogs/wp-content/uploads/2016/11/Close-Outlook-Files.jpg "Close Outlook Files") 2. Go to “File” > “Account Settings”. In the “Account Settings” dialog box, switch to “Data Files” tab, under which you can click “Remove” button to disconnect the PST Files.![Remove PST Files]( "Remove PST Files") ## **Solution 2: Reduce the Memory Cache Size for Each PST File** If you still wish to keep all the PST files in Outlook but the Outlook error persists, here is another approach. You can reduce the memory cache size which Outlook assigns to each PST files. Take the following steps: 1. For a start, close Outlook and head to “Start Menu”. 2. Then type “regedit” in search box and press “Enter” key button. 3. In the Registry Editor, browse to the keys below: “HKEY\_CURRENT\_USER” > “Software” > “Microsoft” > “Office” > “\” > “Outlook” > “PST”. 4. Next right click on “PST” key and choose “New” > “DWORD Value”.![Create a New DWORD Value under PST]( "Create a New DWORD Value under PST") 5. Name the newly created value as “UseLegacyCacheSize”. 6. Later specify its value data as “1”.![Speicify Value Data of UseLegacyCacheSize]( "Speicify Value Data of UseLegacyCacheSize") 7. Ultimately close Registry Editor and restart Outlook. ## **Solution 3: Fix the Issue by Running Scanpst.exe** Nevertheless, if you don’t have multiple PST files connected to Outlook currently but you still encounter the issue, it is more likely that something goes wrong with your PST files, such as small errors or corruptions. In this situation, you have to use Scanpst.exe to scan and repair PST files. You can quickly find out the built-in repair tool under the installation directory of Outlook application. After running it, just follow the onscreen instructions to complete the repair process.![Fix the Issue by Running Scanpst.exe]( "Fix the Issue by Running Scanpst.exe") ## **Solution 4: Recur to a More Reliable Repair Tool** Even though Scanpst,exe is free and handy, it cannot make effects if the PST files are corrupted severely. And at times the inbox tool can make things worse. Thus it is prudent to get hold of an experienced and more cogent repair tool, such as [DataNumen Outlook Repair](https://www.datanumen.com/outlook-repair/). It can figure out the root causes of PST corruptions and extract maximum Outlook data in quick time. ## **Author Introduction:** Shirley Zhang is a data recovery expert in DataNumen, Inc., which is the world leader in data recovery technologies, including [sql recovery](https://www.datanumen.com/sql-recovery/) and outlook repair software products. For more information visit [www.datanumen.com](https://www.datanumen.com) Share Now: - - - - - - - - [← Previous post](https://www.datanumen.com/blogs/3-ways-tick-number-letter-word-document/) [Next post →](https://www.datanumen.com/blogs/create-two-sided-nameplate-word/) Comments are closed. ![Data Recovery Blog]() Follow or like us on Facebook, LinkedIn and Twitter to get all promotions, latest news and updates on our products and company. - - - ### Featured Products - [DataNumen Outlook Repair](https://www.datanumen.com/outlook-repair/) - [DataNumen SQL Recovery](https://www.datanumen.com/sql-recovery/) - [DataNumen Exchange Recovery](https://www.datanumen.com/exchange-recovery/) - [DataNumen Access Repair](https://www.datanumen.com/access-repair/) - [DataNumen Excel Repair](https://www.datanumen.com/excel-repair/) - [DataNumen PDF Repair](https://www.datanumen.com/pdf-repair/) - [DataNumen Word Repair](https://www.datanumen.com/word-repair/) - [DataNumen Zip Repair](https://www.datanumen.com/zip-repair/) ### Popular posts ```json {"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.datanumen.com\/blogs\/4-solutions-outlook-error-memory-system-resources\/#article","isPartOf":{"@id":"https:\/\/www.datanumen.com\/blogs\/4-solutions-outlook-error-memory-system-resources\/"},"author":{"name":"AuthorCCW","@id":"https:\/\/www.datanumen.com\/blogs\/#\/schema\/person\/33ded6c47c77587f9158d99f05e23957"},"headline":"4 Solutions to Outlook Error “Out of memory or system resources”","datePublished":"2016-11-01T03:08:13+00:00","dateModified":"2025-09-29T14:21:08+00:00","mainEntityOfPage":{"@id":"https:\/\/www.datanumen.com\/blogs\/4-solutions-outlook-error-memory-system-resources\/"},"wordCount":614,"commentCount":4,"publisher":{"@id":"https:\/\/www.datanumen.com\/blogs\/#organization"},"image":{"@id":"https:\/\/www.datanumen.com\/blogs\/4-solutions-outlook-error-memory-system-resources\/#primaryimage"},"thumbnailUrl":"https:\/\/www.datanumen.com\/blogs\/wp-content\/uploads\/2016\/11\/Out-of-memory-or-system-resources.png","articleSection":["Outlook Solutions"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.datanumen.com\/blogs\/4-solutions-outlook-error-memory-system-resources\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.datanumen.com\/blogs\/4-solutions-outlook-error-memory-system-resources\/","url":"https:\/\/www.datanumen.com\/blogs\/4-solutions-outlook-error-memory-system-resources\/","name":"4 Solutions to Outlook Error “Out of memory or system resources”","isPartOf":{"@id":"https:\/\/www.datanumen.com\/blogs\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.datanumen.com\/blogs\/4-solutions-outlook-error-memory-system-resources\/#primaryimage"},"image":{"@id":"https:\/\/www.datanumen.com\/blogs\/4-solutions-outlook-error-memory-system-resources\/#primaryimage"},"thumbnailUrl":"https:\/\/www.datanumen.com\/blogs\/wp-content\/uploads\/2016\/11\/Out-of-memory-or-system-resources.png","datePublished":"2016-11-01T03:08:13+00:00","dateModified":"2025-09-29T14:21:08+00:00","description":"More often than not, the Outlook error “Out of memory or system resources” usually occurs when you connect too many PST files in considerable size to Outlook. 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