Qt decoder failed to initialize

Whenever I open Resolve, I get a message popping up with the login page that says "qt decoder failed to initialize". I can still create new projects, but none of my mp4 files are showing up in the library. Resolve worked fine when I first installed it, and I don't recall any changes to my laptop that could have affected it. I have tried uninstalling Resolve and Quicktime and reinstalling with the Resolve installer multiple times without success in fixing the qt decoder error. I tried compatibility mode (windows 8) and running the program as admin, neither were successful. Any suggestions are appreciated.

Davinci Resolve Lite 11.3.1
Asus vivobook s550c
intel core i7-3537u, 2.0GHz
8gb memory
cuda 7.0.28

Thanks in advance!

[Dwaine Maggart]

In Windows Control Panel - Programs and Features, uninstall QuickTime 7 and Resolve.

Reinstall Resolve, and make sure you select the Resolve installer dialog checkbox to install QuickTime as well as Resolve.

Hi Dwaine,
I have already tried that multiple times without success. I reinstalled QuickTime with the resolve installer, and tried redownloading the installer from the website as well.

[Dwaine Maggart]

In Task Manager, in the Processes tab, with "Show processes from all users" selected:

With Resolve not running, is there a QTDecoder.exe task shown?

With Resolve running, are there any QTDecoder.exe tasks shown? If so, how many?

What version of Windows are you using?

QTDecoder.exe appears only when Resolve is running. There is only one and it shows up as "QTDecoder.exe (32 bit)". I am using Windows 8.1. Thanks.

I tried installing it on my PC with similar results. I couldn't get it to work, but my laptop is my main priority. Any insight is appreciated. Thanks.

[Dwaine Maggart]

With Resolve running, select QTDecoder.exe in Task Manager, and End Task.

Then restart Resolve.

Is it working now?

Unfortunately not. I still get the same Qt decoder message.

[Dwaine Maggart]

Are you using a firewall or anti-virus/anti-malware program other than the Windows Firewall and Windows Defender?

I'm using Windows Firewall and Rogers Online Protection. Turning off the firewall had no effect on the problem with Resolve.

[Deleted: Not sure why but it duplicated the post instead of editing the original.]

FWIW: I just installed Resolve 12 and am having the same issue. I do not see a resolution on this thread but will do further research to determine what I can.

Running Windows 10.

In my case, running the installer as Administrator and then setting the app to run as Administrator has resolved the issue.

I also get this same error when attempting to play ProRes 4444 clips and often times when the clips are 4k or above in resolution. Many times this error won't show up with a message but any quicktime clips will no longer respond or go offline.

Everything plays fine in Adobe Premiere Pro just not DaVinci Resolve.

It won't even crash Resolve it just freezes the media and I cannot restart Resolve unless I force quit out of DPDecoder instances as well as QTDecoder instances.

This last freeze it has 8 instances of DPDecoder and 2 of QTDecoder.

This has been a serious issue for me since Resolve 9 and I would like to see a solution as it has been an issue on numerous PC machines I have worked on.

My system:
Windows 7 64bit, Intel i7 8core CUP, x99WS motherboardboard, 2x 12gb Titan X GPU's, 32gb ddr4 ram....

Hi, I'm managed to reinstall latest itunes which have QT installer inside it
After that I tried to open clip with right click -> open with quicktime. When it succeed playing the clip, then I open resolve. Problems gone.

None changing QT properties nor Resolve.
Everything back to normal.

This is happened when I installed others sofware that used QT too.

Sorry my bad english

I see this is an old post, but I had this very same issue and I was happy when I was able to solve the problem. I will post the solution, which worked for me. Just for the case somebody is still using the old version 12 and is struggling to find a solution...

So, the solution has 2 steps. You have to give administrator privileges to both of the apps. It is not enough giving it just to the Resolve.exe.

1. Go to the ProgramData\Blackmagic Design\DaVinci Resolve\Support\QtDecoder\ folder and find the QTDecoder.exe. Enable the "run this program as an administrator" option in the properties at the Compability tab.

2. Apply the exact same stuff for the Resolve.exe as well, by which you start the software.

This was done on Windows and for the version 12. It solved the problem and I hope it will help you as well, in case you happen to stumble on this problem...

I would advise not to connect that machine to the internet, though. It is highly vulnerable.