Thread:Project:Support desk/Problems after upgrading to 1.22/reply (5)

Googling around I could find some possible causes:
 * Bad session manager
 * I've seen various errors related to this when using some opcode cache, e-accelerator, apc, etc. Probably not the opcode fault
 * Not enough memory (that would explain when you get "Allowed memory size of NNNNN bytes exhausted")
 * Some say increasing PHP's  sometimes solves the problem

But nothing conclusive :(