Something that came up during the early days of EB2 development, was the discovery of a siege battle CTD related to "long paths". The "long path" CTD is what happens when you have long folder and file names that concatenate into a character string in excess of 129 characters. As an example, if you installed M2TW and just followed the default folder and file name recommendations (and then added EB2), it would look like this:

C:\Program Files (x86)\Medieval II Total War\mods\EBII\

So even before the game started looking for specific files, you'd have used 52 characters! The team has done it's best to keep file names short, but there are still a lot of directories, so it would behoove folks to make the front end of the string as short as possible (for example, mine is C:\Games\M2TW\mods\EBII\). In addition to avoiding the Siege Battle CTD, there is anecdotal evidence that "shorter paths are more stable", so we highly recommend that everyone take this into consideration.

The "long path" problem is exacerbated for Steam users since the default steamapps directory is 139 characters, so anybody who uses that is basically doomed. Accordingly, if you have the Steam version of the game, we highly recommend that you move your steam library as described in this tutorial.

Lastly - and although the two issues aren't linked - it's worth noting that Windows 10 installations are SIGNIFICANTLY less stable than Windows 7. Accordingly, if at all possible, you should be using Windows 7 as the O/S for your M2TW/EB2 installation.