b44720d5__Installer_3_7___Release_Notes__Known_Issues
[Component] Installation: Performance issue related to digital signing [Change Request] N/A [Known Issues] 
If the signed installer is located on a network share then the entire file needs to be transmitted (to the local machine) before installation can commence. This is because the entire file needs to be read in order to verify the digital signature. Workaround: If you plan to run the quest installer frequently it is advised to copy the installation bundle to a local hard drive.
Quest Installer 3.7 – Release Notes
Known Issues