All the prints get stuck to FEP

[MistaBreed]

Hello everybody!

I got a couple of days ago an Elegoo Mars from Amazon (I don't know if that makes any difference, but mine doesn't have a batch number, in case helps
in identifying the model in any way.)

I'm seeing the same issue as xcyx: no print ever succeeded, not even the test print (two towers rooks) that came with the machine.
All the prints ends up stuck to the FEP layer (which got a couple of rinkcles after the first failed print).

I'm using two strips of masking tape on the short edges of the LCD as suggested to void suction on LCD itself.
Currently I'm thinking to change the FEP, in case the problem could be the damage from the first failed print.
Is it possible that the FEP is not tight enough? (this is how it came from the producer.) Before changing it I
wanted to be resolve the issue with adhesion though...

Things I tried:
- bed leveling as per manual, with a sheet of paper (Nothing stuck to build plate, rooks stuck on FET)
- bed leveling on the empty vat (Nothing stuck to build plate, rooks stuck on FET)
- bed leveling on vat on top of sheet of paper (Nothing stuck to build plate, rooks stuck on FET)

Now, in the last days I have done some testing  and found out this:
- Prints seems to adhere decently fine along the long sides of the build platform, but not in the middle!
I printed 9 small squares 10x10x5 and the 6 on the lines come out fine. The three in the middle row got stuck on the FEP (no support used).
- Same conditions as the test above, but with the squares 'empty' (made a square hole in each of them, leaving a 1mm thick wall), this *should* reduce
vacuum on FEP (right?) because of smaller contact surface. No support. Analogous result as the previous test, just one more piece got stuck on FEP.
- The holding nuts for the build platform must be tighten really a lot to hod firmly the build plate itself (I?m not sure if this is normal, but
seems too aggressive to be correct)

Any ideas to try more?

Best regards

NOTE: attached the test files I used

Had the same issues in the beginning, so let me ask some questions:
What resin do you use?
What temperature has the room you are printing in?
Have you used any stuff on the print plate, maybe for cleaning? Do you have scratches on that surface of that plate?

Me got a lot of failed prints because I was using translucent resin and using the slicing options for default (Black or grey resin). You may need to increase (maybe double) the lighting time.
And I got some really bad prints because I tried printing in my garage because of the smell. The Problem with printing in your garage is the temperature. 4°C is just too less... So nothing sticked on my plate.
And a colleague of mine had used some sort of cleaner that prevented his prints from sticking in the right place.

Maybe your plate is not perfectly calibrated? here is the official way to do that.

Now I use the right lighting times, the right temperature (ok, nearly, it's about 18 or 19°C in my room) and never use sth. else than the plastic spatula on the plate. OK, IPA is the only cleaning detergent I use.
So maybe you can change sth. and test it.
Sorry, I did all the Try and Error myself.