There was a bug for some in v10RC25 with RAM use when emptying cache in setup wizard & config & upgrading - see 0002981: Allowed memory size - Composr CMS feature tracker for a workaround. Sorry for the inconvenience.

Blunder number 2 is RC26 got skipped. That wasn't intentional, my fault because I accidentally raised the release number twice. No harm caused though, just maybe a bit of confusion.