You can:
a) Watch replays if them were recorded with the same version(patch) that you have now; this is for both, vCoH and EF.
b) If you have replays from 2.600 there's an utility on GR to convert from that version to 2.601, this is for vCoH.
You can't:
a) Watch replays from vCoH on EF and vice versa. Different versions.
b) Watch replays below 2.601 if you have full patched your vCoH. Also you can't watch replays below 1.11 if EF is up to date. Different versions.
In my experience:
If you watch a replay with "Sync error" and the game proceeds in a correct way, perhaps the file is corrupted.
If you watch a replay with "Sync error" and the game proceeds in a "weird way", most likely you are trying to view an outdated replay.
P.S. While trying to see the replay I realize that got the same error that our comrade hans... GodlikeDennis, do you use 1.111? :SEDIT: Whoops! I have uninstalled, reinstalled and updated EF and now works
![Tongue :P](https://easternfront.org/forums/Smileys/classic/tongue.gif)
. The good thing about uninstall is that the files remaining are never meant to be there
![Wink ;)](https://easternfront.org/forums/Smileys/classic/wink.gif)
. @Hans remember to patch to 1.111 after 1.11.