Anyone else seen this?

Designer 4.5.3/Windows 2012 R2
Creating or Editing a PRD hangs when attempting to open the PRD for

Happens repeatedly on one Designer install (Windows 2012 R2) but not on
our locally installed copies of Designer.

Copying the workspace from the problematic install to local machine
allows editing/creation - so the issue is not the workspace.

Same designer.ini settings (except for install path)
Disabled antivirus.