Corrupt data DVD recorder

First of the model is DMR-EH55, (not sure it the ‘B’ makes a difference) I have old videos on the HDD, so I took the HDD out of the DVD recorder machine and hooked it up to my computer to attempt a transfer of data.
Upon installing the HDD back I get a message from the DVD recorder that the HDD needs to format before I can use it.
Formatting is no an option because of the videos on it. So I have it hooked up to my PC again and attempting a data recovery.

Any suggestions on why it needs to format, since all I originally did was remove the HDD and then put it back.
Or anything that I should do or not do.
All I want is the data on the HDD.

In order for your PC to work with it, it must have made some small changes that your DVR doesn’t like. Not much you can do but format it like it asks.

That is what i do not wish to do until I can retrieve the data off the HDD.
I am doing data recovery right now and hopefully I can get something.