Yes, a large PST file can cause the “Out of Memory or System Resources” error in Microsoft Outlook. Although modern computers may have sufficient RAM, Outlook still has limitations when handling oversized PST files. When a PST file grows too large, Outlook may struggle to load emails, calendars, contacts, and other mailbox data efficiently. As a result, users may experience frequent freezing, slow performance, crashes, or memory-related error messages.
Large PST files increase the amount of data Outlook must process during searches, synchronization, indexing, and folder navigation. This places additional pressure on system resources and can trigger the “Out of Memory or System Resources” error, especially when working with large mailboxes or multiple Outlook data files. Older Outlook versions are particularly vulnerable because they have stricter file size limitations.
To resolve this issue, users should reduce the size of their PST file by archiving old emails, deleting unnecessary messages, and removing large attachments. Outlook’s Mailbox Cleanup tool can help identify and manage items consuming significant storage space. Creating separate archive PST files is also an effective way to keep the primary mailbox size manageable.
In addition, repairing the PST file with Outlook’s Inbox Repair Tool (ScanPST.exe) can help if the file has become corrupted. Regular mailbox maintenance, disabling unnecessary add-ins, and keeping Outlook updated can further improve performance and prevent resource-related errors. By managing PST file size proactively, users can significantly reduce the likelihood of encountering Outlook memory and system resource issues.