I use Folder Marker Pro 126.96.36.199 for changing series of folder icons or colors in Opus (9).
It is within a database with appr.150.000 Folders.
After about 100 changes of folders Opus freeze.
I then have to disable Opus completely in theTask Manager or restart my desktop PC.
I installed DO12 and all my experience with the Do9 program has dissapeared. Wish I could go back, but it seems that does not work. And back in time does not work in my W10 OS anymore. First problems: I lost my download map and doubleclicking on a file extension is not working anymore. Lots of things have changed, it will cost me day's to understand and find out how 12 works... I knew that Dir Opus is a program with fantastic possibillities but I'm not trained to fly a fighter jet, or need the technology of such a plane. A Piper Cup would do.
The double clicking is the most important one at this moment, can you give me some help?
If you install one version over the top of the other (i.e. don't uninstall first, which will wipe the config), it should import most settings. Toolbars get reset to defaults, but the old ones are still there. ( Your old toolbars are still there after you upgrade )
Going direct from 9 to 12 is a big jump though, so a lot of things may have changed. That is literally 10 years of difference.
If you need help with setting up particular things again, please start a new thread for each thing (unless they are related), and give more detail. (e.g. Which extension isn't doing what you want on double-click? What do you want it to do?)
If i double clicked on a cbr file (digital comics, it's an extension renamed rar file) Opus 9 gave me a comic reader (comic Rack) which I had connected to the cbr. The comic reader is still connected to the cbr file but now I got a number of separated jpg files in a map. As if the original rar file is unpacked by WinRar.
I was reading some comments of you about the double click issue. I have DOpus Dir in the taskbar and a DOpus Help file. Not the file you mentioned there as dopusRT.exe. (PGauld May 2 - 2017)