Every so often Outlook Express compacts messages. It would appear as though some time last week, when it was doing so, it wiped several of my e-mail folders down to nothing. I do have a back-up – a couple of months old – but I was just wondering if anyone knew of a way to merge the back up with the existing folder files, so that I don’t lose the material accumulated since I did the back-up. All help gratefully received.

And yes, it’s another hint to take me off Microsoft completely.

UPDATE: found this, which (hopefully) will do most of the work:

The BAK files your OE folders before compacting. They are copied there
as a precaution in case something goes wrong with the compacting.

1) Look in OE at Tools, Options, Maintenance, Store Folder for the
location of your Store Folder. Then close OE.

2) Go to Recycle Bin and restore the most recent Sent Items.bak file.
That will put it in OE Store folder, but still as a BAK file.

3) Open the Windows File Explorer and look at the store folder you found
in step 1. (You may need to enable the the display Hidden and System
files in Tools, Folder Options, View as well as uncheck the option to
Hide extensions of known file types. You should see both a Sent
Items.dbx file as well as the Sent Items.bak. Rename the Sent Items.DBX
to Sentold.dbx and then rename Sent Items.Bak to Sent Items.DBX. When
you open OE, your Sent Items messages should be restored.