Instant Cleanup: PST Migrator Feature In-Depth

Instant Cleanup: PST Migrator Feature In-Depth


As part of our features in-depth series, here we’ll dig into the Instant Cleanup feature within PST Migrator. Instant Cleanup was added to PST Migrator to automatically find empty Outlook PST files and remove them.

Empty PST files

When a PST file is empty, it still exists on the filesystem as a small file – 271,360 bytes to be exact – but has no data objects within it. Since PST files are actually small databases, the size of the file comes from the data structure within it; just with no data.

Where do empty PST files come from?

Empty PST files are usually created by accident; when Outlook is launched and can’t access an existing PST file, it will prompt the user to locate it or create a new one – a prompt that is easy to click-through and a new empty PST file is generated. There’s no data in it, so the end user typically finds the correct PST, and the empty is left. Over time, these accumulate and almost every customer we’ve worked with has them in their environments.

There is another type of PST file – Outlook integration PST – that also appears as an empty PST file. Internet Calendar Subscriptions creates a PST file to manage that Outlook feature with a PST file is that empty but supports that integration for Outlook. SharePoint Lists integration with Outlook also creates a PST file that is the empty 265KB size. Both of these support Outlook features, but do not store data within them.

Instant Cleanup

  • Within PST Migrator, when Instant Cleanup is enabled, it will:
    • Search for 265KB (271,360 byte) size PST files
    • Evaluate them against the InUseProtectionDays setting in the configuration – for example, the default for this setting is 180, which means that any empty PST file with a modified timestamp older than 180 days will be deleted; anything more recent will not. This can be set to 14 days or more.
    • Delete the PST files meeting the configuration settings by moving them to the local Recycle Bin on the Windows Endpoint running PST Migrator. This is done just in case the file needs to be recovered for some reason.
      • NOTE: when Instant Cleanup runs on network shares, it will move the empty PST files locally first, then move them to the local recycle bin as a failsafe since there is no recycle bin recovery for files deleted over the network.


For PST files – with data – migrated by PST Migrator, the application has always been able to automatically remove the migrated PSTs when they are processed after a configured time interval. The Instant Cleanup feature expands PST Migrator’s capabilities by including empty PSTs as discussed above and further simplifying migration and cleanup of PST files for our customers.


Watch here for a demo of how the feature works.