DaVinci Resolve 12.5 Studio crash and won't start up

I just installed Davinci Resolve 12.5 Studio in the iMac at my office and it always crashes at start up.
I already tried to uninstall and reinstall the software. Also, that dongle is correctly connected, so I don't understand what is wrong.　I appreciate any help you can give me. The specs of my computer are the following ones:

iMac (retina 5K, 27-inch, late 2015)
OS：High Sierra (10.13.4)
Procesor：4 Ghz Intel Core i7
Memory：32GB 1867 MHz DDR3
Graphics：AMD Radeon R9 M395 2048 MB
Storage: 500GB Flash Drive
Additional monitors: None

[Dwaine Maggart]

If you are truly using Resolve 12.5.0, that won't work under High Sierra.

The oldest Resolve version that works in High Sierra is Resolve 12.5.6.

You can find all Resolve versions back to 10.1.5 here:

https://www.blackmagicdesign.com/suppor ... and-fusion