I just recently used this shorter article, below. But of course, before that I actually upgraded to Windows 10.
Pre-Req, Upgrading to Win 10
- I had to uninstall Cisco VPN before upgrading to Windows 10, or else I'd have no networking ability.
If you're in Win 10 after upgrade and didn't uninstall Cisco first, you likely have no networking ability. Just Revert to Win 7, and then upgrade to Win 10 again.
Then, after clean Win 10 upgrade, I was able to use the below steps
Install Sonic Wall Global VPN (for required items)
Install Cisco VPN via .MSI file (I used a copy we already had, 64 bit 5.0.7 for Win 8) (Also, if you run the .exe you'll see an error message that doesn't get thrown if you install via the .msi)
Fix Registry if needed (Remove the crap off the beginning of the Display Name for key HKEY Local Machine\SYSTEM\CurrentControlSet\Services\CVirtA , which in my case became "Cisco Systems VPN Adapter for 64-bit Windows".)
Apparently, some people won't need to fix the registry, but I was getting a 442 error after entering credentials, and fixing the registry did the trick. Similar people are saying similar things about other error messages such as 443.
UPDATE: This may only work on very early version of Windows 10, and may stop working with later updates. Moving to Cisco Any Connect or other software is highly encouraged. Also, as Bers points out, Cisco VPN Client is no longer supported. So, we've likely now gone far past the point where making this work temporarily was still an idea.