UT4 has suddenly stopped working and keeps crashing on start up

I was downloading maps from a hub on UT4 and then it suddenly crashed and the UE4 Crash reporter came up and said that ‘An unknown process has crashed’ and in the summary info it says this MachineId:D97EAE5C4678CFA0F6D1B5A7C6D39AEE.

Now every time I try and launch the game it comes up with the same message. I have tried reinstalling but it didn’t make a difference.

Any help is appreciated, thank you.

I have the same problem when I run the game. Here is my summary info: MachineId:33DCE0F74FEE76D64CBF069EC4D97654
EpicAccountId:537843a271ab49228f4aa9002d0c3c14