Thanks for this advice. If I enter
sudo kextcache -system-prelinked-kernel I got:
Can't open CFBundle for /System/Library/Extensions/prl_hid_hook.kext.
Can't open CFBundle for /System/Library/Extensions/prl_hypervisor.kext.
Can't open CFBundle for /System/Library/Extensions/prl_netbridge.kext.
Can't open CFBundle for /System/Library/Extensions/prl_usb_connect.kext.
Can't open CFBundle for /System/Library/Extensions/prl_vnic.kext.
Can't open CFBundle for /System/Library/Extensions/prl_hid_hook.kext.
Can't open CFBundle for /System/Library/Extensions/prl_hypervisor.kext.
Can't open CFBundle for /System/Library/Extensions/prl_netbridge.kext.
Can't open CFBundle for /System/Library/Extensions/prl_usb_connect.kext.
Can't open CFBundle for /System/Library/Extensions/prl_vnic.kext.
Kernel file /mach_kernel does not contain requested arch: i386
and if I enter sudo kextcache -system-caches
Can't open CFBundle for /System/Library/Extensions/prl_hid_hook.kext.
Can't open CFBundle for /System/Library/Extensions/prl_hypervisor.kext.
Can't open CFBundle for /System/Library/Extensions/prl_netbridge.kext.
Can't open CFBundle for /System/Library/Extensions/prl_usb_connect.kext.
Can't open CFBundle for /System/Library/Extensions/prl_vnic.kext.
Can't open CFBundle for /System/Library/Extensions/prl_hid_hook.kext.
Can't open CFBundle for /System/Library/Extensions/prl_hypervisor.kext.
Can't open CFBundle for /System/Library/Extensions/prl_netbridge.kext.
Can't open CFBundle for /System/Library/Extensions/prl_usb_connect.kext.
Can't open CFBundle for /System/Library/Extensions/prl_vnic.kext.
Can't open CFBundle for /System/Library/Extensions/prl_hid_hook.kext.
Can't open CFBundle for /System/Library/Extensions/prl_hypervisor.kext.
Can't open CFBundle for /System/Library/Extensions/prl_netbridge.kext.
Can't open CFBundle for /System/Library/Extensions/prl_usb_connect.kext.
Can't open CFBundle for /System/Library/Extensions/prl_vnic.kext.
Can't open CFBundle for /System/Library/Extensions/prl_hid_hook.kext.
Can't open CFBundle for /System/Library/Extensions/prl_hypervisor.kext.
Can't open CFBundle for /System/Library/Extensions/prl_netbridge.kext.
Can't open CFBundle for /System/Library/Extensions/prl_usb_connect.kext.
Can't open CFBundle for /System/Library/Extensions/prl_vnic.kext.
Can't open CFBundle for /System/Library/Extensions/prl_hid_hook.kext.
Can't open CFBundle for /System/Library/Extensions/prl_hypervisor.kext.
Can't open CFBundle for /System/Library/Extensions/prl_netbridge.kext.
Can't open CFBundle for /System/Library/Extensions/prl_usb_connect.kext.
Can't open CFBundle for /System/Library/Extensions/prl_vnic.kext.
Can't open CFBundle for /System/Library/Extensions/prl_hid_hook.kext.
Can't open CFBundle for /System/Library/Extensions/prl_hypervisor.kext.
Can't open CFBundle for /System/Library/Extensions/prl_netbridge.kext.
Can't open CFBundle for /System/Library/Extensions/prl_usb_connect.kext.
Can't open CFBundle for /System/Library/Extensions/prl_vnic.kext.
All these mentioned files are from PD7, which I had installed long time ago. I thought I removed it completey, but now I think anywhere in the system are arrears. So how could I get rid of these errors?