System Information:
OS: Mac OS 11.2
Device: MacBook Pro 2019
Parallels:
Parallels Desktop 16
Version: 16.1.3
Kali:
"uname -a" gives
Kali Linux 5.10.0-kali3-amd64 #1 SMP Debian 5.10.13-1kali1 (2021-02-08) x86_64 GNU/Linux
I tried posting this on the Kali forums but even after waiting weeks it never actually passed the comity. 
I originally thought this was a problem with Kali, however I'm not 100% sure anymore:
Description of problem:
I mounted the Parallels Tools cdrom, copied it to my desktop, ran chmod 700 on the install file and ran it with sudo.
It goes though a couple messages then says "Please wait while installing is in progress." This last about 3 to 5 seconds then gives this error:
"An Error occurred when installing Parallels Tools. Please go to /var/log/parallels-tools-install.log for more information."
The contents of said log is attached.
The important lines appear to be these:
Code:
Err:2 http://http.kali.org/kali kali-rolling/main amd64 Contents (deb)
File has unexpected size (39503686 != 39499265). Mirror sync in progress? [IP: 169.229.226.30 80]
Ign:3 http://http.kali.org/kali kali-rolling/contrib amd64 Contents (deb)
Ign:4 http://http.kali.org/kali kali-rolling/non-free amd64 Contents (deb)
Reading package lists...
E: Failed to fetch http://http.kali.org/kali/dists/kali-rolling/main/Contents-amd64 File has unexpected size (39503686 != 39499265). Mirror sync in progress? [IP: 169.229.226.30 80]
E: Some index files failed to download. They have been ignored, or old ones used instead.
Return code from apt-get update is 100
I also had this problem error I tried to run "apt update", which was solved by changing '/etc/apt/sources.list' to refer to kali-last-snapshot instead of kali-rolling, however this still did not fix the Parallels Tools Install.
While this looks a lot like a problem with Kali I was unable to reproduce this problem in Virtual Box.
Things I have tried:
apt update, apt upgrade and apt dist-upgrade.
Reinstalling Kali.
Trying this at least 7 times over the last few weeks, and in the process have in total mounted and copied the cdrom 4 times in case of an update.
Rebooting mac and Kali.
Quitting and relaunching Parallels.
Disabling firewall on mac.
I need to be able to use Bluetooth in Kali and if this doesn't get resolved soon I may have to resort to using Virtual Box and buying a usb Bluetooth dongle (because VB can't use the internal one).