Back up mail messages to OneDrive

Every Microsoft account comes with 15GB of free storage at   OneDrive . This makes it ideal for keeping an automatically updated backup of your mail messages. Here’s a slightly geeky way of doing it, using junctions to keep OneDrive in sync with your store folder. Be very careful when following these instructions – pressing the wrong key might lead to irreversible data loss. You have been warned, so don’t blame me if it all goes pear-shaped. That said, it’s working perfectly for me. Note that the old name – SkyDrive – is still used in some places.

The OneDrive program comes with Windows Essentials 2012. If it’s not already installed, do so: Download OneDrive. Set it up following the prompts.

The WLMail store folder contains a lot of stuff that it’s neither necessary nor wise to back up. For example, the file Mail.MSMessageStore is the index keeping track of all your messages. If you’re in a situation where you need to restore messages from a backup, this large file won’t be much use.

As an example of how to create a real-time back up, here’s how to do it with your storage folders.

  1. Open the OneDrive folder in your user profile. You can do this by double-clicking on the OneDrive icon in the notification area (‘system tray’ by the clock). In this folder, create a new folder and call it, say, Mail Storage.
  2. Open your store folder. To find it, in WLMail’s main window, press Ctrl-Shift-O for Options. On the Advanced tab, click Maintenance and then Store folder. Copy the path there into the start search box and press Enter.
  3. Type   cmd   into the start search box and press Ctrl-Shift-Enter. Give UAC permission when asked. This will open a command window with administrator privilege. You now have three windows open: an Explorer window open at your OneDrive folder, another one open at your store folder and a command window, which is probably black. Resize the windows so you can always see the command window.
  4. Switch to the OneDrive window, then Shift-right-click on the ‘Mail Storage’ folder name and select Copy as path.
  5. Switch to the command window, click inside it, type   cd   and a single space, then right-click and select Paste. Press Enter. If you did this properly, you should now see something like this:
  6. Switch to the window showing your store folder. Shift-right-click on Storage folders and select Copy as path.
  7. In the command window, type   mklink /J “Storage folders”   and a single space, then right-click and select Paste. You should see something like this:
    Click to see the full image
  8. Press Enter. If you did this properly, you should see a message like this:
    Click to see the full image

That’s all there is to it. Storage folders in WLMail is now linked to Storage folders on OneDrive and will remain in sync.


You should treat these backup folders on OneDrive as strictly read-only. If you muck about with files in them, the results are unpredictable. The whole path from the message in WLMail to the .eml file at OneDrive is two-way, so any change to the file anywhere on the path will affect it everywhere it appears. For example, if you delete a file from one of the OneDrive folders, you may find that in due course after synchronizing this change all the way back to WLMail, the program has re-created the file with a new name. Deleting, moving or copying messages should all be done within WLMail to avoid problems with the message database.

Because the backup folder in OneDrive on your computer is a virtual one, it won’t (at the moment) be synchronized automatically by the OneDrive app. It will only synchronize when a sync takes place for some other reason, for example making a change in one of the real folders. You can get around this shortcoming by using a little batch file to force a sync.

Junctions (like Mail storage in the instructions) can’t be deleted in Explorer. If you want to remove the junction you created at step 7, open an administrator command window (step 3 above) and Change Directory to your OneDrive folder (e.g. type   cd “C:\Users\NB\SkyDrive” and press Enter ). Then use Remove Directory (rd): type   rd /S “Mail storage” and press Enter  (the /S switch removes the apparent contents of the virtual directory before removing the directory itself).