ES20 wants me to format a disc with stuff already recorded on it

I have a Panasonic DMR-ES20 and have 2 discs (Memorex DVD-RW) that i haven’t finalized yet, one with 4 hours of stuff and the other with 2 hours. I
took the 2 hour one out of the machine to record something on another
disc and then put it back in the machine 2 minutes later and now
suddenly it says that the disc needs to be formatted to use.
ummm…no i’ve already used it! It’s doing the same thing to the 4
hour one, but there are 2 other discs i have that aren’t finalized
that are just fine. I’m fully aware that formatting it will erase all
of my work. I really can’t lose 6 hours of stuff! Any suggestions on how to fix this? If I bought another es20 would it at least finalize the discs, or do you think the discs are the problem? help!

Good news is any unfinalized disc recorded on one Panny should play and finalize just fine on another Panny. Bad news is I think your disc is corrupted, possibly by your ES20.
I don’t know if you ever hear a grinding noise coming from your machine when trying to read discs, but it you do it’s not a good sign. It means there is disc slippage. The spindle that holds the disc from slipping is probably dirty. You will need to take your machine apart to clean the spindle. No amount of CD lens cleaning discs will touch the spindle.
What happens is every time a recordable disc is inserted in the machine it does a test record to the inner part of the disc. If the disc slips during this record is can be disaster, ruining your R disc, or making you reformat your RW/Ram’s. And wiping out everything on the disc. I think??? this is what may have happened to your RW disc.
I know of no way to reclaim your material.
You should clean the spindle if you are hearing this grinding, it will only get worse, ruining more and more recordable discs for you.
Here’s a link talking about cleaning the spindle.

I’m pretty sure there was any type of grinding noise while it was trying to read the disc. I tried inserting it several times just to make sure the disc wasn’t dirty and the machine wasn’t just having a retard moment, and never heard anything, but I also didn’t have my ear right close to it either. This is something to definitely check out though, thanks!

Since Memorex is crap media having problems is not a shock