This sounds more like a directory/folder structure issue than After Effects.
Maybe run whatever disk titles you have on your Output To location to verify that volume.
What's weird is that when I close the message that says "file path no longer exists", I click render again and then it works as expected. The issue seems to be with trying to "move up" a directory in the template. This worked before but isn't working on the latest version for me. Here is what my custom path is...
[projectFolder]\..\Renders\After Effects\FINAL RENDERS\[compName].[fileextension]
As I said, this same command line worked fine in the last version but is screwed up in the latest. Very frustrating
Hi Evil Edison,
Are you still facing this problem? If not, let us know how you solved it. If so, please let us know so we can assist you further.