Hammer Stops loading a vmf at 5%

Garry's Mod mapping
#1

Any ideas as to the solution? Shouldn’t have anything to do with the vmf as I havn’t added anything in the past 3 days. It loaded fine yesterday and I didn’t add anything, any ideas as to the solution?

#2

Restart hammer/Steam/Source SDK?

#3

Try and follow this tutorial.

#4

If it returns some sort of error, your VMF may be corrupt. Just grab a backup copy from C:/HammerAutosave