Missing mix found and resized/removed" error on project open breaks audio sync

Darius_Leistner · August 31, 2026, 4:42pm

Hi everyone,

I am frequently getting this kind log when opening my project file:

Errors found when opening project file:
A1 00:01:16:18 Clip (chain14) with missing mix found and resized
A1 00:01:43:19 Clip (chain15) with missing mix found and resized
A1 00:02:09:06 Clip (chain15) with missing mix found and removed
…

What I observe:

After the project opens, clips on A1 (audio that’s mostly grouped with video) have shifted/changed size, gaps appear between clips, and the audio goes out of sync with the video tracks.
If I save the file, those clip changes become permanent.

Questions:

What edit actions (e.g., cutting, trimming, moving clips) trigger these “missing mix” errors on same-track transitions?
How can I fix or clean the project file so Kdenlive opens it cleanly without shifting or removing clips?
What is the best editing practice to prevent this from happening on audio tracks in the future?

System Details:

Kdenlive Version: Version 26.08.0 (MLT 7.40.0)
Install Type: Native package via `pacman`
OS: Arch Linux

Terminal Log Snippet (End of opening sequence):

Construct keyframemodel. Checking model: false
Found 1 , OUT:  6910 , animation properties:  "00:03:50.200=0"
ADD keyframe 6906 ; VAL:  QVariant(double, 0) false
add lambda 6906 QVariant(double, 0) false
REGISTRATION  695 ptr count 3
XML parsing of  "qtblend" . found 5 parameters
::::::::::SETTING EFFECT PARAM:  "rect"  =  "6927=0 0 1920 1080 1.000000"
::::::::::SETTING EFFECT PARAM:  "rotate_anchor"  =  "6927=0.5 0.5"
::::::::::SETTING EFFECT PARAM:  "rotation"  =  "6927=0"
END parsing of  "qtblend" . Number of found parameters 5
Construct keyframemodellist. Checking model: false
Construct keyframemodel. Checking model: false
Found 1 , OUT:  6933 , animation properties:  "6927=0 0 1920 1080 1.000000"
ADD keyframe 6927 ; VAL:  QVariant(QString, "0 0 1920 1080 1.000000") false
add lambda 6927 QVariant(QString, "0 0 1920 1080 1.000000") false
Construct keyframemodel. Checking model: false
Found 1 , OUT:  6933 , animation properties:  "6927=0.5 0.5"
ADD keyframe 6927 ; VAL:  QVariant(QString, "0.5 0.5") false
add lambda 6927 QVariant(QString, "0.5 0.5") false
Construct keyframemodel. Checking model: false
Found 1 , OUT:  6933 , animation properties:  "6927=0"
ADD keyframe 6927 ; VAL:  QVariant(double, 0) false
add lambda 6927 QVariant(double, 0) false
REGISTRATION  696 ptr count 3
XML parsing of  "qtblend" . found 5 parameters
::::::::::SETTING EFFECT PARAM:  "rect"  =  "00:03:51.200=0 0 1920 1080 1.000000"
::::::::::SETTING EFFECT PARAM:  "rotate_anchor"  =  "00:03:51.200=0.5 0.5"
::::::::::SETTING EFFECT PARAM:  "rotation"  =  "00:03:51.200=0"
END parsing of  "qtblend" . Number of found parameters 5
Construct keyframemodellist. Checking model: false
Construct keyframemodel. Checking model: false
Found 1 , OUT:  6939 , animation properties:  "00:03:51.200=0 0 1920 1080 1.000000"
ADD keyframe 6936 ; VAL:  QVariant(QString, "0 0 1920 1080 1.000000") false
add lambda 6936 QVariant(QString, "0 0 1920 1080 1.000000") false
Construct keyframemodel. Checking model: false
Found 1 , OUT:  6939 , animation properties:  "00:03:51.200=0.5 0.5"
ADD keyframe 6936 ; VAL:  QVariant(QString, "0.5 0.5") false
add lambda 6936 QVariant(QString, "0.5 0.5") false
Construct keyframemodel. Checking model: false
Found 1 , OUT:  6939 , animation properties:  "00:03:51.200=0"
ADD keyframe 6936 ; VAL:  QVariant(double, 0) false
add lambda 6936 QVariant(double, 0) false
REGISTRATION  697 ptr count 3
XML parsing of  "qtblend" . found 5 parameters
::::::::::SETTING EFFECT PARAM:  "rect"  =  "6944=0 0 1920 1080 1.000000"
::::::::::SETTING EFFECT PARAM:  "rotate_anchor"  =  "6944=0.5 0.5"
::::::::::SETTING EFFECT PARAM:  "rotation"  =  "6944=0"
END parsing of  "qtblend" . Number of found parameters 5
Construct keyframemodellist. Checking model: false
Construct keyframemodel. Checking model: false
Found 1 , OUT:  7018 , animation properties:  "6944=0 0 1920 1080 1.000000"
ADD keyframe 6944 ; VAL:  QVariant(QString, "0 0 1920 1080 1.000000") false
add lambda 6944 QVariant(QString, "0 0 1920 1080 1.000000") false
Construct keyframemodel. Checking model: false
Found 1 , OUT:  7018 , animation properties:  "6944=0.5 0.5"
ADD keyframe 6944 ; VAL:  QVariant(QString, "0.5 0.5") false
add lambda 6944 QVariant(QString, "0.5 0.5") false
Construct keyframemodel. Checking model: false
Found 1 , OUT:  7018 , animation properties:  "6944=0"
ADD keyframe 6944 ; VAL:  QVariant(double, 0) false
add lambda 6944 QVariant(double, 0) false
REGISTRATION  698 ptr count 3
XML parsing of  "qtblend" . found 5 parameters
::::::::::SETTING EFFECT PARAM:  "rect"  =  "12248=0 0 1920 1080 1.000000"
::::::::::SETTING EFFECT PARAM:  "rotate_anchor"  =  "12248=0.5 0.5"
::::::::::SETTING EFFECT PARAM:  "rotation"  =  "12248=0"
END parsing of  "qtblend" . Number of found parameters 5
Construct keyframemodellist. Checking model: false
Construct keyframemodel. Checking model: false
Found 1 , OUT:  12426 , animation properties:  "12248=0 0 1920 1080 1.000000"
ADD keyframe 12248 ; VAL:  QVariant(QString, "0 0 1920 1080 1.000000") false
add lambda 12248 QVariant(QString, "0 0 1920 1080 1.000000") false
Construct keyframemodel. Checking model: false
Found 1 , OUT:  12426 , animation properties:  "12248=0.5 0.5"
ADD keyframe 12248 ; VAL:  QVariant(QString, "0.5 0.5") false
add lambda 12248 QVariant(QString, "0.5 0.5") false
Construct keyframemodel. Checking model: false
Found 1 , OUT:  12426 , animation properties:  "12248=0"
ADD keyframe 12248 ; VAL:  QVariant(double, 0) false
add lambda 12248 QVariant(double, 0) false
XML parsing of  "volume" . found 1 parameters
::::::::::SETTING EFFECT PARAM:  "level"  =  "0=0"
END parsing of  "volume" . Number of found parameters 1
XML parsing of  "qtblend" . found 5 parameters
::::::::::SETTING EFFECT PARAM:  "rect"  =  "0=0 0 1920 1080 1"
::::::::::SETTING EFFECT PARAM:  "rotate_anchor"  =  "0=0.5 0.5 0 0"
::::::::::SETTING EFFECT PARAM:  "rotation"  =  "0=0"
END parsing of  "qtblend" . Number of found parameters 5
REGISTRATION  699 ptr count 3
XML parsing of  "qtblend" . found 5 parameters
::::::::::SETTING EFFECT PARAM:  "rect"  =  "00:10:23.267=0 0 1920 1080 1.000000"
::::::::::SETTING EFFECT PARAM:  "rotate_anchor"  =  "00:10:23.267=0.5 0.5"
::::::::::SETTING EFFECT PARAM:  "rotation"  =  "00:10:23.267=0"
END parsing of  "qtblend" . Number of found parameters 5
Construct keyframemodellist. Checking model: false
Construct keyframemodel. Checking model: false
Found 1 , OUT:  18758 , animation properties:  "00:10:23.267=0 0 1920 1080 1.000000"
ADD keyframe 18698 ; VAL:  QVariant(QString, "0 0 1920 1080 1.000000") false
add lambda 18698 QVariant(QString, "0 0 1920 1080 1.000000") false
Construct keyframemodel. Checking model: false
Found 1 , OUT:  18758 , animation properties:  "00:10:23.267=0.5 0.5"
ADD keyframe 18698 ; VAL:  QVariant(QString, "0.5 0.5") false
add lambda 18698 QVariant(QString, "0.5 0.5") false
Construct keyframemodel. Checking model: false
Found 1 , OUT:  18758 , animation properties:  "00:10:23.267=0"
ADD keyframe 18698 ; VAL:  QVariant(double, 0) false
add lambda 18698 QVariant(double, 0) false
XML parsing of  "luma" . found 6 parameters
QLocale: Default value is QVariant(QString, "") parsed: ""
::::::::::SETTING EFFECT PARAM:  "resource"  =  ""
END parsing of  "luma" . Number of found parameters 6
===== QUERYING TRANSITION:  "mix"
===== QUERYING TRANSITION:  "qtblend"
################### ProjectClip::setproducer #################
################### ClipController::updateProducer
// replace finished:  "14"  :  <tractor>
YYYYYYYYYYYYY DISABLING EFFECT:

// NULL Keyframes---------
// NULL Keyframes---------
// NULL Keyframes---------
// NULL Keyframes---------
YYYYYYYYYYYYY DISABLING EFFECT:

// NULL Keyframes---------
// NULL Keyframes---------
// NULL Keyframes---------
// NULL Keyframes---------
YYYYYYYYYYYYY DISABLING EFFECT:

// NULL Keyframes---------
// NULL Keyframes---------
// NULL Keyframes---------
// NULL Keyframes---------
YYYYYYYYYYYYY DISABLING EFFECT:

// NULL Keyframes---------
// NULL Keyframes---------
// NULL Keyframes---------
// NULL Keyframes---------
=== FOUND THUMB IN CACHE
=== FOUND THUMB IN CACHE
=== FOUND THUMB IN CACHE
=== FOUND THUMB IN CACHE
=== FOUND THUMB IN CACHE
Loading audio levels from cache "/home/darius/Youtube/00_Template/kdenlive/cachefiles/1786454474827/audiothumbs/{8a151b97-0849-48e3-80bc-42de2d67006c}_0_30_audio.dat"
Loading audio levels from cache "/home/darius/Youtube/00_Template/kdenlive/cachefiles/1786454474827/audiothumbs/{94305e1e-c49b-4610-aa9e-163fb99096ce}_0_30_audio.dat"
Generating audio levels for stream 0 of "/tmp/kdenlive-KwtaWR.mlt" using MLT
Generating audio levels for stream 0 of "/tmp/kdenlive-mfZZYc.mlt" using MLT
Audio levels generation took 7.613 s ( 528.964 frames/s)

(Note: I have both the full .kdenlive project file and the complete terminal log saved locally. If you need either file to reproduce or inspect this issue, please let me know where I can safely upload them!)

berndmj · August 31, 2026, 5:21pm

Hi @Darius_Leistner, and welcome to the forum and community.

You are using your distro’s version of Kdenlive which may have introduced issues during packaging (libraries, dependencies, etc.). Normally, I’d suggest to try the AppImage or the Flatpak but these are not yet ready (Flatpak might, but AppImage isn’t).

So, once the official announcement has been posted I suggest to try the AppImage. If the problem persists, please open a bug report. Thanks!

Darius_Leistner · September 1, 2026, 10:26am

Thank you so much! I didn’t realize AppImages and Flatpaks don’t follow a rolling release model. This saved me a lot of potential headaches in the future with mid-project updates.

I ran some tests using “tricky edits” with timeline mixes on both the Flatpak and AppImage versions, and they seem to behave the same way. While the issue still feels somewhat unpredictable, I isolated a few specific actions that seem to trigger it:

Main observation: Trimming or deleting clips with mixes attached while performing ripple operations seems to cause the timeline corruption.

Scenarios where it happens:

Using the “Resize Item End” (or Start) shortcut on a clip with a mix while the Ripple Tool is active.
Using the “Extract Clip” shortcut to remove multiple clips when some of those clips share a mix with adjacent clips that are not being extracted.
Undoing these specific ripple actions sometimes triggers or worsens the timeline state.

Temporary Workaround: For now, avoiding ripple edits on clips with active mixes seems to prevent the issue from happening.

I will check the bug tracker to see if there is an existing report for this mix/ripple behavior. If not, I’ll compile these observations into a bug report.