Parallels Tools fail every time at 74% on Parallels Desktop 10.
prl_fs driver fails to install
This issue is still under investigation by the Development team.
Use a possible workaround below:
1) Take snapshot.
2) Unmount Parallels Tools iso image from the virtual machine (Devices > External Devices > CD/DVD > Disconnect).
3) Make sure Parallels Tools iso image is not present in My Computer.
4) Uninstall Parallels Tools through Programs and Features and restart the virtual machine.
5) Download and mount the attached fixed iso image below to (Devices > External Devices > CD/DVD).
6) Install Parallels Tools.
Note: tell the customer to ignore Parallels Tools yellow question mark on the right top virtual machine corner that offers to update.