Merge archive files or other pst-files

Sadly, there is no easy way to merge them directly but there are some workarounds for this.

Depending on the amount of pst-files and their sizes, you can either combine them manually or use the Import/Export wizard to combine them into one big “Master Archive”.

As an alternative, you could also use a 3rd party tool specialized in merging pst-files.

Preparation: Opening archives to view its contents

As technically an archive is no different from any other pst-file, you can reconnect them to Outlook to access and view their contents via;

• File-> Open & Export-> Open Outlook Data File…

Preparation: Creating a Master Archive

Since you are going to create one big archive, I recommend that you start off with a new pst-file which will become your “Master Archive” and then copy the contents of all your archives into this single archive instead of appending any existing archive. This way, you’d still have the original in case a merge goes wrong.

1. Create a new pst-file. This will be your “Master Archive”.
   • File-> Account Settings-> Account Settings…-> tab Data Files-> Add…
2. Choose a location and name for the archive file and a display name for it in Outlook when prompted.
   • I recommend a folder called Outlook in your Documents folder. Either way, make sure you do not select a network location as that is not supported.
   • If you get prompted for a type of storage file, do not select the 97-2002 version as you’ll archive will be limited to 2GB then (pst-files created in Outlook XP/20002 and previous will always be limited to 2GB).

Method 1: Manual Merging process

If you like to have more control over the merging process, then manually copying over your previous archive into the new Master Archive is the recommended way to go. Especially when the copying process fails, it is easier to determine where it went wrong so you can prevent creating duplicates when resuming.

This method also gives you the opportunity to adjust the folder structure or combine folders with a similar topic but a different name.

1. Connect one of you old archives to Outlook if it hasn’t been connected yet:
   • File-> Open & Export-> Open Outlook Data File…
2. Copy the contents from the original archive to the new “Master Archive”. You can copy entire folders or even folder structures at once.
   Use the right mouse button instead of the left when dragging and dropping to make sure you are copying.
3. To easily move Calendar items, switch it to a List View via the View menu or View tab.
4. Once done copying, disconnect the original archives via the Remove button on the Data Files of your Account Settings.
   • File-> Account Settings-> Account Settings…-> tab Data Files
5. If you want the new “Master Archive” to be your default archiving location, you can change the location in;
   • File-> Options-> Advanced-> button: AutoArchive Settings…
   • For more details and screenshots see: Creating a new Archive pst-file and changing the folder for AutoArchive to archive to.

Method 2: Using the Import feature

You could use the Import option as well to import your original archives into a new “Master Archive”. However, the Import process gives you less control in selecting a different destination location on a per-folder or even per-item basis.

The Import process is also known to freeze on occasion. When it works, it is definitely the faster option. When it hangs, it is hard to find out where it got stuck and from which point you need to continue the import process to prevent duplication.

When you go for the Import option, keep in mind the following 4 things;

• Scan all your pst-files with scanpst.exe first as errors in the pst-file can hang the import process.
• Make a backup of all your pst-files (and possibly your Exchange mailbox) before starting with importing and create a new backup after each successful import.
  This way, when an import goes wrong, you don’t have to fiddle with cleaning up manually. Simply restore the backup (replace the pst-file when Outlook is closed) and try again or use the manual method as indicated above.
• Make sure you select the “Master Archive” as the destination for the import process. If you forget this, your archive will import into your main mailbox instead.
• Outlook may appear to be “Not Responding” during the import process while in fact it is still importing. Occasionally look at your master archive pst-file in File Explorer to see if it is still growing. If so, Outlook is actually still responding.

You can find the Import command in Outlook under;

• File-> Open & Export-> Import/Export

Method 3: Add-in alternative: Stellar Merge PST

If you find the above process too much work or if you find yourself regularly needing to merge pst-files, then using Stellar Merge PST might be the solution for you.

Stellar Merge PST isn’t actually an Outlook add-in as it works as a standalone application. It allows you to easily select 1 or more pst-files and merge them into a new pst-file, an existing pst-file or your current mailbox. It also supports merging to mailboxes that aren’t based on a pst-file such as an Exchange on-premises mailbox or a Microsoft 365 mailbox.

There are several merging options available such as eliminating duplicates, skipping the Deleted Items and/or Junk Email folder. It also supports password protected pst-files.

There is also an option simply join the pst-files together so that each pst-file has its own folder structure within a new or existing pst-file or mailbox. This is a great option to add data of a colleague that has just left the company to your own mailbox.

View: Stellar Merge PST

The Home tab of Stellar Merge PST. (click on image to enlarge)