First, send an email from the new mail profile and note the time/date when you sent the email. This time/date will be important shortly.
Now, go to:
You're looking for two autocomplete files. Both files start with stream_autocomplete . . .
You're looking for one stream_autocomplete file with the time/date when you sent the email just now.
You're also looking for the stream_autocomplete that is much larger and represents the autocomplete for the old profile (this will be a file between 10 KB and 5000 KB) with a time/date that corresponds to the last time you sent an email from the old profile.
We'll call the new file "new_autocomplete" and the old file "old_autocomplete" going forward.
Open Outlook. Put Outlook offline.
in c:\users\%username%\appdata\local\microsoft\outlook\roamcache . . .
Highlight new_autocomplete and choose rename. Hit control C so you have the name of new_autocomplete in your clipboard. Add a single letter to the end of new_autocomplete so new_autocomplete now has a new name.
Highlight old_autocomplete_copy and choose rename. Paste the name you have on your clipboard. Now, your copy of old_autocomplete will have new_autocomplete's name.
Wait 30 seconds
Put Outlook onlne.