Conversion failed. A required codec could not be found or failed to install

Plex Media Server
1

Server Version#: Version 4.152.0
I know this is a common issue and have tried everything suggested on the site with no luck. Certain media files of TV episodes play fine, however, I’m getting this error when I play another episode of the series or play the episode that worked just fine 5 minutes ago. I’ve tried everything and am still at a loss. Log is attached if anyone could please help. Thanks!

Plex Media Server Logs_2025-10-23_21-33-58.zip (3.7 MB)

2

Check in the directory tree where PMS is stored

The drive which which the PMS instance is running on does not have exec permission as part of the mount.

(Boot filesystems are always mounted with exec privilege set but additional drives are often mounted with noexec option)

Start looking there

Oct 23, 2025 21:31:28.403 [23292419459896] ERROR - [Req#28f/Transcode] Unzip: could not set executable bit on output file
Oct 23, 2025 21:31:28.403 [23292419459896] ERROR - [Req#28f/Transcode] CodecManager: failed to extract zip
Oct 23, 2025 21:31:28.403 [23292419459896] ERROR - [Req#28f/Transcode] Error configuring transcoder: Decoder install failed: eac3_eae
Oct 23, 2025 21:31:28.403 [23292419459896] DEBUG - [Req#28f/Transcode] Streaming Resource: Terminating session 0x152f329048b8:eobyz41koxqxygl4rv9cwh1j which is using 1532kbps of WAN bandwidth.  Used is now 0kbps
Oct 23, 2025 21:31:28.403 [23292419459896] DEBUG - [Req#28f/Transcode] Streaming Resource: Terminating session 0x152f329048b8:eobyz41koxqxygl4rv9cwh1j which is using transcoder slot.  Used slots of 10de:1f82:3842:1057@0000:01:00.0 is now 0
Oct 23, 2025 21:31:28.403 [23292419459896] DEBUG - [Req#28f/Transcode] Streaming Resource: Terminated session 0x152f329048b8:eobyz41koxqxygl4rv9cwh1j with reason Conversion failed. A required codec could not be found or failed to install.
Oct 23, 2025 21:31:28.403 [23292459719480] DEBUG - [Req#28f/Transcode] Killing job.
3

I think I’m seeing it, what is the best way to fix this?

4

The easiest way to fix this is :

  1. Go to the Docker menu

  2. Get into the PMS container’s Console

  3. From here, using the command line, cd down into the Codecs directory

    Screenshot from 2025-10-31 14-05-39
    Screenshot from 2025-10-31 14-05-391209×878 54 KB

  4. ls -la and you’ll see the UUID for the actual codecs

  5. Delete (rm) everything except the .device_id file (your license)

  6. Now exit and restart the container. It will download fresh copy of the codecs

5

Thanks, Followed your instructions but the problem is still there.

6

Anything else I can try?

7

I’ve been experimenting.

Given this is the error:

Oct 23, 2025 21:31:27.928 [23292419459896] INFO - [Req#28f/Transcode] CodecManager: obtaining EAE
Oct 23, 2025 21:31:27.928 [23292419459896] DEBUG - [Req#28f/Transcode/HCl#90] HTTP requesting GET https://plex.tv/api/codecs/easyaudioencoder?build=linux-x86_64-standard&deviceId=ab235b06-682a-4f42-8921-fcace7ee0c42&oldestPreviousVersion=legacy&version=8f4ca5ead7783c54a4930420
Oct 23, 2025 21:31:28.175 [23292434406200] DEBUG - [HttpClient/HCl#90] HTTP/1.1 (0.2s) 200 response from GET https://plex.tv/api/codecs/easyaudioencoder?build=linux-x86_64-standard&deviceId=ab235b06-682a-4f42-8921-fcace7ee0c42&oldestPreviousVersion=legacy&version=8f4ca5ead7783c54a4930420
Oct 23, 2025 21:31:28.176 [23292455623480] DEBUG - [Req#28f/Transcode/GetFile/HCl#91] HTTP requesting GET https://downloads.plex.tv/codecs/8f4ca5ead7783c54a4930420/linux-x86_64-standard/EasyAudioEncoder-linux-x86_64-standard.zip
Oct 23, 2025 21:31:28.377 [23292434406200] DEBUG - [HttpClient/HCl#91] HTTP/2.0 (0.2s) 200 response from GET https://downloads.plex.tv/codecs/8f4ca5ead7783c54a4930420/linux-x86_64-standard/EasyAudioEncoder-linux-x86_64-standard.zip
Oct 23, 2025 21:31:28.403 [23292419459896] ERROR - [Req#28f/Transcode] Unzip: could not set executable bit on output file
Oct 23, 2025 21:31:28.403 [23292419459896] ERROR - [Req#28f/Transcode] CodecManager: failed to extract zip
Oct 23, 2025 21:31:28.403 [23292419459896] ERROR - [Req#28f/Transcode] Error configuring transcoder: Decoder install failed: eac3_eae
Oct 23, 2025 21:31:28.403 [23292419459896] DEBUG - [Req#28f/Transcode] Streaming Resource: Terminating session 0x152f329048b8:eobyz41koxqxygl4rv9cwh1j which is using 1532kbps of WAN bandwidth.  Used is now 0kbps
Oct 23, 2025 21:31:28.403 [23292419459896] DEBUG - [Req#28f/Transcode] Streaming Resource: Terminating session 0x152f329048b8:eobyz41koxqxygl4rv9cwh1j which is using transcoder slot.  Used slots of 10de

Did you move the transcoder temp, by settings in PMS, mounts, or external symlinks, to another location?

The problem is because PMS, as it unzips the codec, can’t make it executable.
We’ve configured all default locations to be executable (for the codecs) so the challenge is to figure out why your configuration isn’t that way

( Is this Unraid’s container image or Plex’s container image ? Looks like Unraid’s)

8

I’m using the Docker in Unraid. Looking PMS settings (both through the app and docker), I am using /transcode for the Transcoder temporary directory.

9

So last night things were working and files that were having trouble were playing, but suddenly this morning the same files I played last night now aren’t and showing the same error as before.

10

Until I blew up my Unraid box last night :collision: — Everything was working fine.

The problem you’re having is because of where the /config folder is placed.
That location doesn’t allow executable files (programs) to be placed.

Docker puts the PMS executables in a different place that has “execute” permission.

When the transcoder (executable program) starts up, it loads the codecs as support modules (which is allowed).

The EAE (EasyAccessEncoder), which is the Dolby program we have to use, gets downloaded and stored with the codecs. If there’s a problem, this is why.

I think, on unraid, folks call it a cache drive (just for data). EAE is a program, not data. Normally PMS would be fine on a cache drive just not the Dolby EAE.

11

Thanks — that makes sense. I didn’t realize the /config directory’s location was blocking executables from running. Given that, what would be the best Unraid configuration to make this work properly?

Should I move the entire /config to a different path (like /mnt/cache/appdata/...), or would it be better to split things so PMS can still use the cache for data but have its executables and EAE stored somewhere with proper execute permissions?

I just want to make sure I set it up in the most reliable way for both the transcode and Dolby EAE modules.

12

It seems to be playing on Firestick, but keep getting the error when watching through a web browser.

13

Firestick can play more codecs natively than the web browser can.
Web browser is the weakest and often the first to require transcoding.

I did manage to recover my machine. (rebuilt the USB)

This is my appdata (container) directory where PMS is stored.

root@Gerbil:/mnt/user/appdata/Plex-Media-Server/Library/Application Support/Plex Media Server/Codecs# ls  -la
total 1004
drwxr-xr-x 1 nobody users     205 Nov 10 18:51 ./
drwxr-xr-x 1 nobody users     276 Nov 10 19:05 ../
-rw-r--r-- 1 nobody users      36 Jun  5 17:23 .device-id
drwxr-xr-x 1 nobody users     244 Jun 27 08:49 46f74ab-560174306fe167a5978a79dd-linux-x86_64/
drwxr-xr-x 1 nobody users      30 Jun 19 18:28 EasyAudioEncoder-8f4ca5ead7783c54a4930420-linux-x86_64/
-rw-r--r-- 1 nobody users 1020638 Nov 10 18:51 EasyAudioEncoder-8f4ca5ead7783c54a4930420-linux-x86_64.zip
root@Gerbil:/mnt/user/appdata/Plex-Media-Server/Library/Application Support/Plex Media Server/Codecs# cd 46f74ab-560174306fe167a5978a79dd-linux-x86_64/
root@Gerbil:/mnt/user/appdata/Plex-Media-Server/Library/Application Support/Plex Media Server/Codecs/46f74ab-560174306fe167a5978a79dd-linux-x86_64# ls -la
total 6196
drwxr-xr-x 1 nobody users     244 Jun 27 08:49 ./
drwxr-xr-x 1 nobody users     205 Nov 10 18:51 ../
-rw-r--r-- 1 nobody users  203928 Jun 10 07:30 libaac_encoder.so
-rw-r--r-- 1 nobody users  300584 Jun  5 18:40 libdca_decoder.so
-rw-r--r-- 1 nobody users 1596496 Jun  5 17:30 libh264_decoder.so
-rw-r--r-- 1 nobody users 1509968 Jun  5 17:30 libhevc_decoder.so
-rw-r--r-- 1 nobody users  124968 Jun 27 08:24 libmp3_decoder.so
-rw-r--r-- 1 nobody users  553200 Jun  5 17:34 libmpeg2video_decoder.so
-rw-r--r-- 1 nobody users  772656 Jun  5 17:38 libmpeg4_decoder.so
-rw-r--r-- 1 nobody users 1132448 Jun  5 17:37 libvc1_decoder.so
-rw-r--r-- 1 nobody users  135120 Jun 27 08:49 libwmav2_decoder.so
root@Gerbil:/mnt/user/appdata/Plex-Media-Server/Library/Application Support/Plex Media Server/Codecs/46f74ab-560174306fe167a5978a79dd-linux-x86_64#

You should have the same/similar