Outlook performance issues caused by large OST files are quite common, especially when the file size grows close to its limit. From my experience, the best way to fix this is by reducing the OST file size and optimizing Outlook settings.
Start by cleaning up your mailbox—delete unnecessary emails, especially those with large attachments, and empty the Deleted and Junk folders. You can also use Outlook’s Mailbox Cleanup tool to find and remove large or old items. Archiving old emails is another effective way to reduce the active OST file size.
Next, try reducing the sync period in Cached Exchange Mode (for example, sync only the last 6–12 months instead of the entire mailbox). This significantly decreases the amount of data stored in the OST file and improves performance.
You should also compact the OST file after cleanup to remove unused space. Additionally, disabling unnecessary add-ins and updating Outlook can help improve speed.
For better handling of large data, using a professional OST Converter can help export important emails to PST or other formats, reducing the OST file load. In my work, I found BLR Tools useful for managing large OST files efficiently and improving Outlook performance without data loss.
Start by cleaning up your mailbox—delete unnecessary emails, especially those with large attachments, and empty the Deleted and Junk folders. You can also use Outlook’s Mailbox Cleanup tool to find and remove large or old items. Archiving old emails is another effective way to reduce the active OST file size.
Next, try reducing the sync period in Cached Exchange Mode (for example, sync only the last 6–12 months instead of the entire mailbox). This significantly decreases the amount of data stored in the OST file and improves performance.
You should also compact the OST file after cleanup to remove unused space. Additionally, disabling unnecessary add-ins and updating Outlook can help improve speed.
For better handling of large data, using a professional OST Converter can help export important emails to PST or other formats, reducing the OST file load. In my work, I found BLR Tools useful for managing large OST files efficiently and improving Outlook performance without data loss.