How long is a tunnel
In this case the answer is easy, it's double of the half length.
It's not easy to say, you draw something and TC shut down (crash)
So you did something TC dont like at all, whatever that was.
Before you start up that drawing again i would recomend that you check for dwl's, they can make it "funny" if they are left
Go to the place you save your drawing and look for filename.tcw.dwl, if there is, delete them and then start TC and open the file again, think a bit if you did something special just before it crash and avoid that.
If it not save the last work you did on it, you can try to open Autosave folder and look for a .asv file for that day and time, or a crush file .crh i belive.
You also have a backup file in the Backup folder .bak
When you find the file that is closest to the crash, open it as a regular drawing and resave as i. e. filename_2.tcw in the original folder for that drawing.
V20, V21, 2015/ 16/ 17/ 18/ 19 Pro. Platinum
Deluxe 2015/ 16/ 19
Windows 10 Home Premium 64 bit, 32 GB
NVIDIA Geforce GTX 780m, 1 GB