I’ve seen numerous posts in this forum regarding the extremely slow installer for 8.5.1, but nobody seems to have any suggestions as to why it happens or how to make it faster. Running in an Windows environment (mixed Win 7 and XP), 32 bit or 64 bit, upgrade or clean install, nothing seems to matter. Doing a “silent” install of the Notes 8.5.1 client is taking anywhere from 30 - 60 minutes. Those kind of times makes it almost impossible to roll out in a corporate environment… telling a user they can’t access e-mail for an hour is like sentencing yourself to an earful. Anyone have any luck making this thing faster?
P.S. - I should mention that the install is local to the C:\ of the computer, it is already unpacked and the data directory is on the local C:\ drive as well. Everything is local and still seeing these slow times
Subject: Disable Anti Virus
Christoph got it right. Disable the Anti virus during Notes installation.
We have McAfee Anti virus running on our PCs. With McAfee running, Notes installation takes up to an hour. With McAfee disabled it finishes in 15-20 minutes. 
Hope you are running the installer from the local hard disk and not from a remote machine.
Subject: RE: Very slow install - Disable virus scan
Thanks for the input. This did seem to help. My install times were cut from 30 - 60 minutes to around 10 - 15. Still not great, but better.
We use SEP (Symantec Endpoint). In case anyone else uses SEP, here is the command line commands to stop SEP…
REM Stop SEP (Symantec Endpoint) Services
C:
cd “\Program Files\Symantec\Symantec Endpoint Protection”
smc.exe -stop
net stop “Symantec Antivirus”
net stop ccEvtMgr
net stop SNAC
net stop ccSetMgr
Good luck all
Subject: disable Virus scan
Did you make a test with your antivirus turned off?
There are a lot of small java-Files which gets scanned during the install. We made a performance win of about 50 % with disabled Antivirus software.
Greets
Chris