Steps I took that resulted in the problem:
It just freezes on startup.
Install was a bit weird: after mounting install image normally, copying to Applications took ~10 minutes. After all, it’s just 334MB…
I tried to download and install it twice.
What I expected should have happened instead:
…
My version of Fritzing and my operating system:
0.9.3b, El Capitan 10.11.5 (15F34)
PS The same version starts normally on my 10.10.4 (14E46) Yosemite.
have the same issue with windows 10. unzipping it took so long and it when i start it it freezes. i tried starting it with different compatibility setups, but no success.
Windows 10, 64 bit
0.9.3b
Hello,
The first start took a while, wait and observe the task manager.
Fritzing was running with 25% CPU usage for some time, then a update window appeared and i freez for some more minutes, after a second update and a restart of the software it finaly works!
All you have to do is wait… 
I’m not sure about MACs, but there is no progress bar on the download so it can look like it’s hung. Just let it sit for 15min.