|9||9||3) a temporal freeze with "formats 0x1 to 'UTF8_STRING'" and "VERR_TIMEOUT" in the log, mentioned by me, @Borrelworst, @simonc and everybody else. It doesn't cause guest to abort or crash on the 126.96.36.199128 testbuild. It is not a permanent freeze, it is just a slight delay (i.e. TIMEOUT) guest continue to run absolutely normal before and after it. This VERR_TIMEOUT was in the logs all the time, 6.1.16 and the testbuild. It seems that you didn't touch it by your patches. To reproduce I just run the WinXP guest, abuse it in some way (kill and run VBoxTray.exe etc) and then copy unicode string from guest to host.