I had a similar error which cypress could not reproduce. It came out for me that I had to do a windows system restore to have my settings applied again.
I think the user.config file got some invalid data.
You can try deleting the user.config file. Then PSoC Creator will generate a new one, I think this will resolve the issue.
You can find user.config in:
C:\Users\XXX\AppData\Local\Cypress Semiconductor\PSoC Creator\3.x
Thanks to you, JOBIN GT
This hint was working and I got back the old feeling when starting Creator.