ERROR: Failed writing to file "C:\windows\system32\Drivers\etc\hosts".
Horizon client adds an entry to the local hosts file and some antivirus apps block access. Disable your antivirus temporarily and try again.
This issue is caused by the host file on the system being read only or other permission restrictions.
If you have a policy that sets the GPO to ready only or antivirus that enforces it.
Change the permissions for the hosts file on the system from read only to read/write and try again.
File Location: C:\Windows\System32\drivers\etc\hosts
You can change this attribute from read-only to read-write mode during the View client installation to allow the installation to proceed and permissions can be reverted after installation to satisfy organizational requirements..