Unable to start Instant Terra because the version is too old.

[ZoltanE]

I just started getting this message after rebooting, when I attempt to start IT from Unreal:

EDIT: If I keep trying then eventually it starts. However even when it does there is no link to Unreal, I'm forever stuck at "Updating terrain - Waiting for Unreal to respond". The Unreal log shows none of the log prints that usually accompany the process.

[Alexis Vaisse]

Obviously something is getting wrong here. Maybe some files have been corrupted.
I suggest you to uninstall Instant Terra, remove the Instant Terra Unreal Engine plugin, download and install the latest version of both Instant Terra and the Unreal Engine plugin.