I’m a Mac user so I can offer only generic advice:
Boilerplate-text:
Are Photoshop and OS fully updated and have you performed the usual trouble-shooting routines (trashing prefs by pressing command-alt-shift/ctrl-alt-shift while starting Photoshop until the appropriate dialog appears after making sure all customized presets like Actions, Patterns, Brushes etc. have been saved and making a note of the Preferences you’ve changed, 3rd party plug-ins deactivation, system maintenance, cleaning caches, font validation, etc.)
And a Forum search for »_MVM_.tmp« would point you to threads like this