Your Outlook AutoComplete list, which suggests email addresses as you type, is not appearing on your other computer. This happens because the nickname cache is stored locally on each device and is not part of your Microsoft 365 cloud sync. This article explains the local nature of the AutoComplete cache and provides a method to manually export and transfer the data file between devices.
Key Takeaways: Managing the Outlook AutoComplete Cache
- File > Options > Mail > Send messages > Empty Auto-Complete List: Clears the local cache on the current computer to remove old or incorrect entries.
- %appdata%\Microsoft\Outlook: The folder path where the Outlook profile’s AutoComplete cache file is stored for manual backup.
- Import/Export Wizard: The built-in Outlook tool for transferring other data types, but it does not support moving the AutoComplete list.
Why the AutoComplete List Does Not Sync Automatically
The AutoComplete feature in Outlook uses a local file often called an NK2 file, though its modern extension is different. This file saves the email addresses you have typed in the To, Cc, and Bcc fields. It is designed as a personal, machine-specific cache to speed up your typing on that particular device.
Microsoft 365 and Outlook.com accounts sync email, calendar, and contacts through the cloud. The AutoComplete cache is intentionally excluded from this sync for performance and privacy reasons. Transferring this data requires a manual process of locating, copying, and replacing the specific cache file on another computer.
The Difference Between AutoComplete and Suggested Contacts
A common point of confusion is the difference between the AutoComplete list and the Suggested Contacts folder. The AutoComplete list is the local cache file discussed here. The Suggested Contacts folder is a cloud-synced folder that Outlook can populate automatically, but it does not control the dropdown suggestions when addressing an email.
Steps to Locate and Export the AutoComplete Cache File
To move your AutoComplete list to a new computer, you must find the file in your Outlook profile folder and copy it. The steps below require you to know the name of your Outlook profile, which is often your email address.
- Close Outlook completely
Ensure Outlook is fully closed on the source computer. Check the system tray for the Outlook icon and exit from there if necessary. - Open the Run dialog
Press the Windows key + R on your keyboard to open the Run command box. - Navigate to the Outlook data folder
Type%appdata%\Microsoft\Outlookinto the Run box and press Enter. This opens the folder containing your Outlook profile data. - Identify your profile’s cache file
Look for a file with a long, complex name and the file extension.dator.nk2. The name typically corresponds to your Outlook profile name. The modern AutoComplete file for Outlook 2013 and later is usually a.datfile. - Copy the cache file to a transfer medium
Copy the identified.datfile to a USB drive, a cloud storage location like OneDrive, or an external hard drive. - Transfer the file to the target computer
On your second computer, close Outlook. Use the same Run command (%appdata%\Microsoft\Outlook) to open its Outlook data folder. - Replace the target computer’s cache file
Paste the copied.datfile from your source computer into this folder. If a file with the same name exists, rename the old one as a backup, then ensure the new file uses the exact same filename. - Restart Outlook and test
Open Outlook on the target computer. Compose a new email and start typing an address from your old computer to verify the AutoComplete list has transferred.
Common AutoComplete Cache Issues and Solutions
Outlook AutoComplete List is Missing After Transfer
If the list does not appear, the most likely cause is a filename mismatch. The cache file name is tied to your Outlook profile name on that specific computer. If your profile name is different on the new computer, you must rename the transferred file to match the new profile’s exact cache filename. Check the folder for the existing file’s name before renaming your imported file.
How to Clear a Corrupted or Bloated AutoComplete List
A list with many old or incorrect entries can be cleared from within Outlook. Go to File > Options > Mail. Scroll to the Send messages section and click the “Empty Auto-Complete List” button. This deletes the local cache file and starts a new one. You will need to rebuild the suggestions by typing addresses again.
AutoComplete Not Working At All in Outlook
First, verify the feature is enabled. Go to File > Options > Mail and ensure the “Use Auto-Complete List to suggest names when typing in the To, Cc, and Bcc lines” box is checked. If it is enabled but not working, the cache file may be damaged. Use the “Empty Auto-Complete List” button to reset it, or try the manual file replacement method using a known-good backup.
AutoComplete Management Methods Compared
| Item | Manual File Transfer | Using the Empty Auto-Complete List Button |
|---|---|---|
| Primary Use | Migrate cache to a new computer | Reset a corrupted or outdated local cache |
| Data Outcome | Preserves all existing address entries | Permanently deletes all cached entries |
| Technical Skill Required | Medium – navigating file system | Low – uses Outlook settings menu |
| Cloud Sync | No – remains a local operation | No – affects only the local profile |
| Best For | Device setup or replacement | Troubleshooting or privacy cleanup |
You can now manually move your Outlook AutoComplete suggestions between computers by managing the local cache file. For ongoing use, remember that new addresses you type will only be saved to the device you are using. A related feature to explore is the Outlook Contact list, which does sync across devices and can be used for reliable addressing. For advanced management, you can use the Windows Registry to point Outlook to a network location for the NK2 file, enabling a form of centralized storage for the cache in a business environment.