Version 3.1.3
Windows 10, 64 bit
Has happened to me twice now...working on a project. Close project. Reopen Project - receive "Failed to open map view." error message.
My project makes use of the reclassify tool in the ModelBuilder. I read a reply in a similar post that indicated they were able to replicate the error after using the Reclassify tool.
I've submitted a Bug Report to Technical Support.