Don't edit until conforming/indexing is finished.
The time will depend on the number of Clips, their Duration, the speed of your system and how much conforming needs to be done, but a bit of patience will pay dividends here. You can watch the little progress bar with the blue scale.
On many systems, PrPro will become unresponsive during this process. That is not really such a bad thing.
Jim's advice is right-on. Maybe a cup of coffee would be in order, while this completes.
Thanks for your replies I just hope this bug will be fixed in the next update.
At least restarting and reloading the project works significantly faster in this version - 4.1
Well, it's not really a Bug. PrPro just needs to do some things first. How long this will take will depend heavily on one's system. How well it will work, if one does not wait for Conforming to complete will also depend on one's system. If all necessary resources are free and in adequate supply, many can happily edit while Conforming is going on. For others, problems or hangs can occur.