To clarify: this would be to test if an asset in the data folder is causing the crashes, or the folder itself? And if it's an asset, it would have been corrupted at some point, and is there any way to find out if that has happened and to what files?
This is the more drastic approach of cutting losses and moving on I suppose.
If you want to look for bad assets in your current install:
1) Go to open for edit folder and revert everything in there that's open for edit.
2) Check for faulty assets and either delete them, or repair them, your choice. It could be one of these too ya know that's causing the CTD.
Be careful of faulty assets. Missing dependencies in this case don't count as faulty. I mean truly faulty.
3) Search for Installed, AND NOT Built-in.
You can add the additional filter choices by clicking on the + on the far right of the screen. If you need to, and this is highly recommended, add in all the columns in Content Manager.
4) Sort by Kuid with lowest first.
I would say sort by date installed, but that gets a bit messed up with fresh installs and updates.
5) Highlight a bunch of assets, perhaps 10 at a time.
6) Click on Content on the menu bar.
7) Choose disable.
8) Run Trainz.
Does it crash?
If not, go back to your list and unhide one at a time. Test and if nothing, move on to the next bunch. Repeat disabling, testing, enabling, until all the assets are covered.
You'll run into something that's hosed, and you can then delete that asset and redownload it again.
Now do you want to do this, or cut your losses, create a new folder, import the routes you created/modified and then download only what you need for those routes again from the DLS. You may also need to install stuff from CDPs if you purchased something from Jointed Rail, or downloaded stuff from third-party websites.
But anyway, this is the long convoluted process. Pick your poison.