Large Outlook Data Files can slow down performance and become difficult to manage. The built-in Archive feature can move old items automatically, but it lacks precise date control. This article provides a manual method to split a PST by specific years or months, creating organized, smaller archives.
Key Takeaways: Splitting a PST File by Date
- Search Folder > Create New Search Folder > Old Mail: Isolates emails older than a specific date for easy bulk selection.
- Right-click > Move > Other Folder > New: Creates a new PST file and moves selected items into it in one action.
- File > Account Settings > Data Files > Add: Opens a new PST file without importing data, ready to receive moved items.
Understanding PST Files and Manual Archiving
A PST file stores your Outlook items locally. As it grows beyond 10 GB, you may notice slower search and general lag. While the AutoArchive tool exists, it works on a single date threshold for all folders. To create multiple archives segmented by precise date ranges, you must use a manual process. This involves creating new PST files and using Outlook’s search and move functions to transfer items. You need write access to the original PST file and sufficient disk space for the new archives.
Steps to Create a Date-Based Archive PST
This method uses a Search Folder to find old items, then moves them to a newly created PST. Repeat the process for each date range you want to archive.
- Create a new PST file for the archive
Go to File > Account Settings > Account Settings. Select the Data Files tab. Click Add. Choose Outlook Data File (.pst), give it a descriptive name like “Archive_2015-2017”, and click OK. The new file will appear in your folder list. - Build a Search Folder for your date range
Right-click on Search Folders in your folder list and select New Search Folder. In the dialog, scroll down and select Create a custom Search Folder. Click Choose. Name it “Old Items for Archive”. Click Criteria, then go to the More Choices tab. Check the box for Only items that are: and select Received from the drop-down. Next to it, select on or before and choose your cutoff date, like 12/31/2017. Click OK to create the folder. - Select and move items to the new PST
The Search Folder will populate with all emails meeting the date criteria. Press Ctrl+A to select all items. Right-click the selection, hover over Move, then click Other Folder. In the Move Items dialog, navigate to and select the new PST file you created, then click New. Name the folder, for example “Inbox Archive”, and click OK. The items will be moved. - Repeat for subfolders and other date ranges
The Search Folder only finds emails. For Calendar, Contacts, or Tasks, you must manually open each folder in your main PST, use the View > Change View > List view, sort by Modified date, select items, and move them to corresponding folders in the new archive PST. To create an archive for a different date range, create another new PST and adjust the date in the Search Folder criteria.
Common Mistakes and Limitations to Avoid
Search Folder shows no results or incomplete items
Search Folders rely on the Windows Search index. If indexing is incomplete, results will be wrong. Ensure indexing is complete via Windows Search settings. Also, Search Folders typically only work for Mail items. They will not find Calendar appointments or Tasks by date. You must process those folders manually.
Moving items deletes them from the original location
The Move command transfers items. They are removed from the source PST. Before starting, back up your original large PST file. Go to File > Open & Export > Import/Export > Export to a file > Outlook Data File (.pst) and select your main mailbox to create a full backup.
The new PST file is not visible in the folder list
After creating a PST via Data Files, it should appear. If it does not, close and restart Outlook. To open an existing archive PST, use File > Open & Export > Open Outlook Data File and browse to its location.
Manual Archiving vs. AutoArchive: Key Differences
| Item | Manual Date-Based Split | AutoArchive Feature |
|---|---|---|
| Date Control | Precise, user-defined ranges (e.g., 2018-2020) | One global “older than” date |
| Process | Manual selection and move per folder | Fully automated, runs on a schedule |
| Output Structure | Can create multiple, organized PSTs by year or project | Moves all old items to one default archive PST |
| Item Types | Works for all item types with manual effort | Primarily designed for email |
| Best For | Creating structured, long-term historical archives | Regular maintenance to keep primary PST size down |
You can now organize a large PST into smaller, date-specific archives. This improves Outlook performance and makes finding old emails faster. For ongoing management, set up AutoArchive rules on your new, smaller primary PST file. Use the Cleanup Tools in File > Mailbox Settings to find and remove redundant messages before archiving.