I just left it running. Because I could see all these shader threads being started up and shut down by the editor.exe I knew it was doing some sort of set up and needed to be left to it.
Now all the shaders are built you’ll have to move to a new engine version to get it to rebuild them all. The launch process should be quick now, as it won’t need to build the shaders again.
Also, you left it an hour before then you killed it. It wouldn’t start over and do that hour again because each thread writes the shader to the hard drive. That hour of work will have been saved, and it would pick up where it left off with the next shader it needs to build. Hence if you’d left it from the very start it would have done 1 1/2 hours of shader compiling time.
If you killed it every 15 minutes, still 1 1/2 hours of compiling would go by, but you’d have restarted 6 times.
Make sense?