VBox 4.0.x hangs x64 host for a minute on VM start

[Szikra]

VirtualBox 4.0.x hangs my host OS for a minute or so every time I start (or resume) a VM. (3.x.x worked fine.) Effects: video playback stops, mouse pointer stops moving... The host is a Windows 2003 x64 Server (64 bit AMD host). guests include 64 bit Ubuntu 10.04 LTS Desktop, 32 bit Windows XP ...

Full log files will be attached. The time of hangs: Ubuntu: 00:00:12.420 AHCI ATA: Ctl: finished processing RESET 00:01:08.959 Display::handleDisplayResize(): uScreenId = 0, pvVRAM=0000000007cdc000 w=640 h=480 bpp=32 cbLine=0xA00, flags=0x1

00:00:06.576 AHCI ATA: Ctl: finished processing RESET 00:01:16.784 ERROR [COM]: aRC=VBOX_E_IPRT_ERROR (0x80bb0005) aIID={09eed313-cd56-4d06-bd56-fac0f716b5dd} aComponent={Display} aText={Could not take a screenshot (VERR_TRY_AGAIN)}, preserve=false

00:00:03.999 Guest Log: BIOS: Booting from CD-ROM... 00:00:51.302 Display::handleDisplayResize(): uScreenId = 0, pvVRAM=00000000079a0000 w=640 h=480 bpp=16 cbLine=0x500, flags=0x1

00:00:05.899 PCI: ahci/0: 16-bit field COMMAND: 3 -> 7 00:01:17.220 TM: cTSCTicksPerSecond=0x94f4f77e (2 499 082 110) fTSCVirtualized=true fTSCUseRealTSC=false (state load)

XP: 00:00:09.579 Guest Log: BIOS: Booting from Hard Disk... 00:01:03.839 PIT: mode=2 count=0x2ead (11949) - 99.85 Hz (ch=0) 00:01:03.951 Display::handleDisplayResize(): uScreenId = 0, pvVRAM=0000000007060000 w=640 h=480 bpp=0 cbLine=0x140, flags=0x1

[Szikra]

Ubuntu_Server_x64

[Szikra]

Ubuntu_Server_x64

[Szikra]

Ubuntu_Server_x64

[Szikra]

Ubuntu_Server_x64

[Szikra]

WinXP32