Exchange Cached Mode Issues? How Splitting OST Files Helps

[Victor Guerrero]

Exchange Cached Mode often causes issues when the OST file grows too large—leading to slow syncing, freezing, delayed email loading, or Outlook becoming unresponsive. This happens because Outlook must constantly read and write to the oversized OST file while syncing with the server.

How Splitting OST Files Helps

Splitting an oversized OST file into smaller parts can significantly improve performance by:

• Reducing sync load on Outlook
• Preventing corruption caused by very large OST files
• Speeding up mailbox access and search results
• Lowering the chances of freezes and crashes
• Making the data easier to manage, back up, and restore

Since Outlook doesn’t include any built-in option to split OST file data, users often rely on a tool like BLR OST to PST Converter, which can split OST files by size, date, or folder structure without data loss.

In Short

• Large OST files = Cached Mode problems.
• Splitting the OST = Faster, smoother, and safer Outlook performance.