Very slow sync on IOS



I have just signed up for the Plex Pass and was looking forward to syncing content to my iPhone or iPad.
The sync speed is soooo slow.
I have 150Mb/s fibre optic broadband and it is taking me around an hour to sync one music album (200Mb).
This should be downloading in a matter of seconds.
Has anyone else had problems with the sync? Very disappointed.



Same here, in local-2-local network. Plenty of people complain about the same for many years already.

My assumption is that the sync goes via Plex servers outside instead of remaining really local-2-local.
Plex Team: Could you please confirm ?


Device: iPhone 6 128GB
OS: iOS 10 (latest available build at time of writing)
Usage pattern: almost exclusively music, syncing things at "High" quality
Yes, I submit analytics data.

I've been struggling with sync speeds on iOS for a while, and it's really quite frustrating (iPhone 6, iOS 10). I'm sure part of my problem is due to having an older phone (~2.5 years at time of writing), but I also happened to grab syssecinfo when it was available, so I have some insight into what's happening.

Whenever I'm performing a sync operation, CPU usage on my iPhone is at 100%. Maybe it will dip down to 96% or so, but it's close enough to 100% that it's not worth distinguishing. I don't know why the CPU usage is so high, but I've run sync operations for long enough that my phone has become uncomfortably warm.

Outside of syncing, Plex is generally just incredibly slow to use: it feels very much like it's running a full Plex Server instance on the phone and talking to it via a wireless network, rather than just accessing local content (my mobile bill disagrees with this statement, but that's what it feels like).

I was under the impression that all the transcoding was happening server-side and my local device was just pulling down the transcoded content. So perhaps its a writing-to-storage thing? Perhaps its doing something weird in the local network? I don't know, but whatever is going on makes my whole phone unusable whenever I'm syncing content -- and using Plex is an increasingly frustrating experience.


Same issue here. Just trying out Sync for the first time and it's still working on a 6-movie playlist for over 24 hours now. Painfully slow. My Plex server is a Mac Mini w/quad core and I'm trying to Sync that playlist to my iPhone which is on the same 802.11ac WiFi network. I looked through the forums and can see people have complained about this issue for years. I'm really surprised this hasn't been resolved. The server and the device are on the same high-speed Wifi; why in the world should it take so long to sync?


I've been using Plex since v3 and the synch feature to my iPad worked perfectly when I was abroad and downloading remotely over wifi to my home when in hotels etc..
Since the upgrade to v4 synch locally has been really slow and remote synch is unusable. I generally live with this, but with a 3 week holiday coming up this long standing fault is going to be a massive pain.

The problem arrived with v4 and was never resolved along with all the other early v4 issues and seems to be a common ongoing problem :smile:

I've tried the one option someone offered up of disabling WAN NAT redirection, but my fairly expensive Draytek Router doesn't appear to have this feature.
Is there any hope this will be fixed, I'm happy to support the dev team with logs, but people have tried this already?


Got the same issue here. Running Wireless 802.11AC in the house, have the plex server on a quad xeon with 200gb of ram, tried multiple os's and it seems that only ios is affected as for android it sync's very fast. I've seen many posts about fancy routers and adjust settings on the network which all these make no sense.


Same here.

No problems with either macOS or Android, but iOS is super slow. I also have wifi AC.


Count me in to this problem. And it seems to be much older, as you can see here:

It is really annoying that I am nearly not able to sync one movie over night.


why not just add the ability to sync via USB cable? Syncing takes too damn long on wifi.


To bring this post back to life. I had the Google Pixel and it would take a couple of minutes to sync a Highest Quality movie to it. I loved it! I switched back to the iPhone X and it’s soul crushingly slow to load a High Quality movie. @gmonroy has a great point, let me connect the damn thing to USB.


It’s always been like this as far as I know. I’ve been a Plex member for years and sync has never worked on iOS. You play a movie at 720 which transcodes fast and buffers nicely along when I’m not at home, yet if I set it to sync at the same 720 resolution, it takes hours. I always end up cancelling it. Compete waste of time.


Same for me!. What is more surprising is to find so much plex pass users having this issue, and no word from plex developers…


@JosePiratilla said:
Same for me!. What is more surprising is to find so much plex pass users having this issue, and no word from plex developers…

You don’t hear from the Plex developers because:
a) they most likely do not know how to fix the issue, that is what happens when you don’t write your own products (like they did not do for the iOS app, the use the built in player)
b) plex as a whole does not care about the end user anymore

I have been using (trying to use) iOS sync since it was released as a feature. It works - mostly - but it is very slow. I am currently re-syncing my music and I will leave my Plex media at that. If I want movies I will get them from Netflix and Amazon (which, Plex, they seem to be able to do much more efficiently, even over LTE - a full movie in less than 5 minutes; yesterday and and today it took me over 13 hours to sync 412 songs [SONGS!!!] - what a joke).


I’m encountering the same speed issues with sync on iOS. I’m completely baffled that downloading anything from the outside world can be faster than downloading a video on my LAN to my iPhone.


Another one to add here. It is just insanely slow and the issue has been there for years.
I cannot understand why this issue is ignored.


This is ridiculous! The only reason i purchased the Plex Pass was to be able to sync my content! It takes hours to convert 1 movie… This is not acceptable


Is there a tutorial or recommendation on how to put video content on an iPhone that syncs and you can watch on a plane? I have kids with an iPhone 6 plus and a 7 and they can’t watch their media on the phone. It only plays audio.


Same issue here as well. Mighty frustrating.


@EasTexHtwn A lot of people don’t like to hear this, but the simplest way to to make sure the media is loaded into Plex in an Apple-compatible format. If it is, and your Sync Quality settings are set to highest, the server will just copy the file to the device and not do any transcoding or re-muxing. My syncing experience has generally been pretty good when doing this, even if I am remote.

The Apple-compatible settings are generally:

  • MP4 container
  • Resolution up to and including full-4K, if you edit the iOS.xmls profile (I havent gotten it to sync 4K without doing this)
  • H.264 or H.265 with the FourCC set to HVC1
  • AAC/AC3/E-AC3/MP3 audio. To keep the server from transcoding file that have multi-channel AC3, I had to edit the iOS.xml file to allow up to 8 channels of audio
  • text based Subtitles (mov_text,tx3g,ttxt,text)

If you encode your own media using Handbrake any of the current Apple device profiles work just fine.

If you obtain your media as MKVs from various sources, you could figure out how to re-mux/transcode it using Subler (MacOS) or FFmpeg (MacOS or Windows), or you could run it through Handbrake, but you’ll probably lose some quality, and takes a lot more time.