I upgraded 2 CCR1036-8G-2S+ Cloud Core Routers from 6.3 to 6.30.2 on 2 different ISPs and get the same issue with both of them.

Since upgrading our PPTP VPN connections are dropping randomly with an error "CCP lost compression got our of sync: disabling compression" then the next message is "terminating... - Encryption got out of sync"

All compression in the PPP Profile is disabled but still receive the error.

It seems to drop within a couple hours if you are pushing a lot of data through the PPTP connection. It will still drop if you are not pushing a lot of data it just may take longer, it seems very random.

I tried factory defaulting one of the routers but it did not seem to help the issue at all.

We have 2 offsite MikroTiks that connect into our Cloud Core and I had to move them over to L2TP without IPSec for stability and they seem to be stable but I can't move our whole VPN over to L2TP, it needs to stay PPTP.

Here is our PPP Profile:

name="VPN" local-address=10.0.0.52 remote-address=VPN use-mpls=default
use-compression=no use-encryption=required only-one=default
change-tcp-mss=yes address-list="" dns-server=10.0.0.27,10.0.0.26

Anyone have any suggestions?

Hi, did you ever get a solution to this?  We've recently started getting the same issue with Win7 clients connecting, but they worked fine before.

I ended up watching the release notes for the PPTP fix and it was finally resolved for us.  

We are currently running v6.34.4 without any PPTP issues.