Similar to Autocomplete settings, Outlook Categories are saved in a Stream_CategoryList_1_guid.dat file. The GUID is random, and looks something like this:
In order to restore Outlook Categories when creating a new profile, you can use the same approach required for restoring Autocomplete files. Basically, rename the old categories .dat file to match the DAT file associated with your new profile.
Here’s what my categories looked like before creating a new profile:
And here is the generic categories that Outlook comes with:
Not only am I missing my custom categories which prevents me from setting the categories I want on all my new emails, I’m also missing the categorization of my old emails – not an ideal scenario at all!
In this case, the category files might be the same size, so use your last modified date to give you an idea of which one you need to bring forward.
In order to import this Category list, make a copy of the one that you want to import, and then rename it to match the default one created by Outlook:
As you can see from the screenshot, I rename the default one to old, and then copy the name of the file to my clipboard. Rename your copy to match this (making sure that the file extension is still is .dat at the end), and voila!
Categories are back in place, and all is well with the world!
Update (July 2017): Going Deeper
After Kevin commented below on having multiple DAT files to try and sort through, I thought I’d take a look to see if there was a better way of figuring out which file holds your categories – trial and error is fine when there’s only a couple of files, but if you have a whole bunch, this gets annoying quickly. I had never tried opening these files in Notepad before, but essentially they’re just XML files, and so you can definitely open them up and find which files have your categories in them.
If I checked my current categories in Outlook, I can see I was actually missing these categories – I uninstalled and re-installed Office, and they ended up getting lost… perfect time to dig in and find my own fix!
So I opened both DAT files in Notepad ++ (if you don’t have it installed, you should – it’s amazing), and found my active file by finding the one that only had the MVP category:
I copy/pasted the lines that I wanted into my active DAT file – always make sure you keep the XML syntax intact – I noticed that my current category colour for MVP was “7”, or blue, which conflicted with my “Stratiform” category. I tried messing around a bit, changing the colour to orange, and replacing the orange line, but it wouldn’t stick when I saved the file:
So all I did from there was open the file back up again, undo my changes (love, love, love Notepad ++), and removed the orange line entirely, and added my MVP category back at the bottom, and all was well with the world again:
I’m sure smarter folks than I could tell me what specifically is happening in those XML files, and whether or not the order actually affects things – all I know is that my categories are back, and I’m in business again! 😀