I think the main problem with AV equipment especially players is that they are just not as well built as they were say in the 80's and 90's.

Last Christmas my player stopped playing BD66’s. After a shocking assessment from a Panasonic repair team that will cost £280 to repair my player I thought screw it, but then I went on Reddit, I opened the player, cleaned the lens and then I had to turn a miniscule screw near the lens and lo and behold, all the discs worked.

I made the upgrade to 4k discs just this year and have been very frustrated with how FRAGILE the format is -- both the discs and the crappy build quality of most of the players. DVDs can look like they were used for coasters for years, scratched all to heck, and they will still play. Blu rays seldom get scratches in the first place and play like a dream, always. With 4k discs... if you cough in their general direction, they start skipping and freezing. Genuinely, a single smudge or scratch will wreck them. It has certainly convinced me to not get rid of any of my blu ray copies of a movie even when I upgrade, as I have the feeling they will outlast the 4ks by many years. It's frustrating, because 4ks often look gorgeous when they work. I haven't given up on the format but wish that I could trust it to be as reliable as blu rays are.

Interesting that no ones memtioned adding a usb stick to the back of the 820. From reading around the internet, its a cache issue and giving it more space can help stop skipping in playback

I’ve been pretty fortunate with my 4 year old Panasonic 820. No real issues with discs at all. Fingers crossed.

These players only overheat for 4k discs,I installed cooling fan and plays without a hitch

The design/material of the surface/piece of furniture on which you place your Blu-ray player could be affecting its performance. I’ve owned a Sony UBP-X800M2 4K Blu-ray player for about two years now (I used to own an X-700M, and I also have an LG UBK90 connected to my LG G3 OLED TV). I use my X800M2 to play both video and audio discs: DVD, Blu-ray, 4K UHD Blu-ray; audio CDs, Blu-ray audio CDs, SACDs… you name it. I too started experiencing similar problems as the ones described ad nauseam here: movies skipping frames, Blu-ray discs freezing, etc. I tried all the different tips shared here (turn off 4K upscaling, etc.), and I think it probably helped (I think). What baffled me was that I also started experiencing the same problems (skipping, freezing…) when playing audio CDs, not just “fancier” formats like SACD, but regular music CDs. It got to a point where I would experience the laser “skipping” and freezing 1 out of every 3 times that I’d be playing a CD. As you all know, all optical disc players have a reader that spins optical discs at very high speeds in order to “read” them with a laser. This made me wonder if, maybe, something about how I had set up my UBP-X800M2 was causing vibrations that were affecting its performance. My UBP-X800M2 Blu-ray player used to sit on top of a Sony A/V receiver; both components used to sit on a small metal shelf. I wondered if the fact that, a) the shelf was small, and b) it was made from metal, meant that there was no vibration dampening at all, but the opposite: vibration amplification. About a month ago, I moved my UBP-X800M2 and placed it on top of a larger, wood particle table with four legs; large enough that I feel that any vibrations do get dissipated by the table. I’ve been testing the unit, playing all sorts of audio and video optical disc formats for hours, waiting for any skipping or freezing, and I have experienced none. I’ve even turned back on 4K upscaling in the UBP-X800M2 settings; still, the skipping and/or freezing issues haven’t reappeared. This might or might not be the cause of the issues affecting your unit, but it’s worth a try asking yourself if just maybe, the design and/or the material of the piece of furniture your Blu-ray player is sitting on might be creating vibrations affecting its performance. Good luck.

Most of these players can’t handle tiny imperfections on these 4k discs. That’s it.

panasonic UB 9000 here.  I Had problems with some discs especial 4k uhd so i started to clean them in a ultrasound cleaner (cheap avaiable from amazon) with a mix of destilled water and isopropanol alcohol. 3 parts water 1 part alcohol and some drops of dishwasher. 4 min of cleaning and i could see some black goo going away from the disc, removed this with a soft brush. let it dry and the problems where gone. it were chemicals from the dvd box. i also started to put the disc upside down in the boxes for avoiding this problem (distance disc to box is bigger.  helped for me 🙂 i wish they would use better boxes for those expensive discs

There's nothing more frustrating than bringing home an expensive new impressive 4K release popping it in the deck and having it freeze up I have been using glasses wipes wiping them as you suggested from the center out this is all common knowledge sometimes that works sometimes that doesn't work and I lean on the fact that maybe my player wasn't top of the line but this issue of freezing shouldn't be happening It doesn't happen on any Blu-ray or any DVD but sure as hell the 4K's all frees up at some point. Very very very very very very frustrating I love my collection and movies are a big part of my life and the reason I upgrade them to such expensive formats is because I want them in the best possible viewing experience and I don't know what else to say It just bugs me.

I repair these players and they always come in with issues when playing 4k discs, the most common reasons are a dirty lens and dried out grease on the mechanism especially the slider rails where it congeals and makes the movement stick with the laser struggling to read the disc. A full service usually returns them to full working order, sometimes a new laser is the only solution. The 820 and 9000 both have the same mechanism and lasers. I have seen players that have issues when new due to a long time in storage. As for the discs they are way more problematic than standard blu ray, and often not worth the price. The difference between them is not worth the hassle and expense in my opinion.

I own now my third Panasonic 9004!
First 2 had major issues with freezes, skipping and artifacts. Always thought its the Discdrive, but i noticed with the second one that the player gets very warm on one specific spot. Plus a while ago i talked to someone who is modding panasonic players and he told me that sometimes in the factory state there are thermal pads missing.
So for my third player i installed a pc fan right under the spot where it got very hot last time. No issues since.

This is why I'm sticking with Blu Ray. Yes, if you have a prime setup (big 4K OLED, Atmos 7.1 system etc) then 4K makes sense, but it's a hell of a lot of data crammed into a space which was originally only designed for 650MB / 700MB and I think this is where the problem lies.

I had that Panasonic 820 and had problems right from the start, returned it and went with the 9000 and haven't any problems since. Hopefully it stays good it's been a few years now.

Its ridiculous we only have 3 to 5 4K UHD players in the market to choose from, especially when there is a TON of new 4K releases from many boutique labels all the time. Most of them too older models already. I share your frustation, I have both the 820 and the 700 from Sony and I haven't had skipping issues so far but they're pretty flimsy in general and the Panasonic is ridiculously messy in the disc tray area. I heard the Panasonic 9000 is practically as problematic as the 820 so.... hope you have a better experience and share it with us.

Afaik it's the much tighter track pitch of a 4k disc over standard blu-ray that makes it more susceptible to surface 'dirt'. There have been known issues with some players and the larger capacity triple layer disc layer change.

I mean before you buy new players, have you tried checking the slide rail that the lens slides on and clean off the old dryad up lubrication and then tried replacing it with a thin layer of white lithium grease on the two rails or even a synthetic clock oil along with also taking a Q-tip and alcohol and cleaning the lens itself.

Cause if the rails not the problem, possibly, if you’re a heavy heavy user, your lens may have finally reached its maximum hours of use, and it just needs to be replaced, which would be cheaper than buying a whole new player

Oppo needs to return.

I've had my Panasonic UB820 for 5 years now and no issue at all so far.

I got a Panasonic UB45k many years ago living in Japan. After years of loyal service it began giving me problems and some discs would skip and freeze badly. Tested on my friends PS5 and the discs were fine. As a player the UB45k is waaaayyy cheaper than the one you have. Doesn’t hurt so much to replace it, which I did. Been a year with another Panasonic ub45 and no issues so far. It’s crappy build quality but has Dolby vision. I keep the older one to play blurays and 4ks it didn’t skip or freeze on. I think over time the laser just wears down.