Note: I am an amateur, this is my first time modelling, rigging etc. Please use simple terms so my dumb untrained brain can understand. Thankyou!

This would be the 3rd time this has happened. I made a rig for my character, bound the skin mesh to the rig skeleton, then painted the paint skin weights in deformed areas when I moved limbs and such around.
I then save and exit the file (because it was 2am, this girl gotta sleep), when I open it the next day, the skin seems to have unbound itself from the rig skeleton and I don't know if my paint weights are even there. Basically, the mesh won't follow the skeleton despite being in its rainbow coloured 'I'm bound' state.

The first time, I just redid the binding process and repainted the weights because my first attempt was pretty bad. Second time, I angrily repainted it and 3rd? Well this is a University assignment that is due tomorrow and I'm still trying to get the stupid mesh to stay with the rig.

I've looked up ways to fix it and could only find this blog of someone with the same situation:
https://forums.cgsociety.org/archive/...t-1121401.html
(although I don't really understand how they fixed it)
I have deleted the mesh history in the past, so I found this really strange. I've tried again and still no positive results.

I've attached a screenshot of the script I receive when I open the file and an example of the model not following the rig.



I really do hope there is a solution or some guidance you could maybe give... because at this point it looks like my only option is to unbind, rebind, paint weight as I have done in the past... but also set up backdrop, light, animate, render all in one go...
This has set me back 3 times now and I'm really annoyed that I have to redo it yet again as I can't seem to get the mesh to stick back onto the skeleton unless I unbind, rebind, repaint.

Any suggestions would be very much appreciated,


P.S. When I was painting the skin weights, I noticed that all my tail joints weren't included in the influence? Only joint 19, which is the tip of the tail. This means I couldn't successfully bind the skin to the tail joints. (I was going to work around that and have no focus on the tail if that were the case, just thought I'd ask as to why that might be happening.) Any solutions to this would also be great, thankyou!