
VBGL_IOCTL_ACQUIRE_GUEST_CAPABILITIES failed rc=-138

09:00:34.130210 automount vbsvcAutomounterMountIt: Successfully mounted 'Music' on '/media/sf_Music' 09:00:34.124961 automount vbsvcAutomounterMountIt: Successfully mounted 'Downloads' on '/media/sf_Downloads' vboxsf: Successfully loaded version 6.1.4 on 5.3.0-28-generic SMP mod_unload (LINUX_VERSION_CODE=0x5030d) vboxsf: Successfully loaded version 6.1.4 vboxsf: g_fHostFeatures=0x8000000f g_fSfFeatures=0x1 g_uSfLastFunction=29 09:00:34.005471 main vbglR3GuestCtrlDetectPeekGetCancelSupport: Supported (#1)

interestingly we see this error in the Linux guest:
