Using At Ease on a 680x0-based Macintosh computer, after installing System 7.5 Update 2.0 and enabling Open Transport with the Network Software Selector, my computer stops responding during startup, while the extensions are loading.
As of March 1996, At Ease is not compatible with Open Transport. This includes all versions, At Ease 3.0.1 and earlier.
Workaround:
Use Classic AppleTalk instead of Open Transport.