P: LrC 15.5 Video Files Issues (Windows)

Same issue in Lightroom Classic 15.6 on Windows 11 Pro. HEVC import fails with "An unknown error occurred while reading the video file". H.264 imports fine.

• GPU: NVIDIA RTX 3060, GPU acceleration on, Studio drivers updated
• Microsoft HEVC Video Extensions (paid version) installed, files play fine in Windows
• File: HEVC Main, 8-bit 4:2:0, constant 25 fps, AAC, exported from DaVinci Resolve
• Tried: remuxing without the timecode track, changing the codec tag from hvc1 to hev1, clearing video cache and dynamiclinkmanager folder – no change
• Confirmed: downgrading to 15.4.1 fixes it

Same issue with a video taken with Canon EOS R6 Mk II FHD in MP4 format. Video is not imported due to unknown error, tried several things supposed by Google AI like rename to MTS or MOV, reformat with shutter encoder. Nothing helped, Size 33GB, lenght about 1.35 hrs. LrC 15.5.1. Windows 11 Pro 26H2. Graphics Nvidia RTX 4060 TI,latest driver.

Same problem here. Videos play fine on Windows but Lightroom can’t import them. This used to work. Still broke in 15.6.

I just updated to 15.6 and the issue persists. Back to 15.4 for me.

Confirming this issue in Lightroom Classic 15.6 (Windows 11).

- Videos: HEVC (H.265) .mp4 files from Pixel 6a and Pixel 10 Pro
- Import fails with "An unknown error occurred while reading the video file" (14 files affected)
- The files play fine in Windows, and they imported fine in earlier versions
- Remuxing the files from hvc1 to hev1 with ffmpeg (-c copy -tag:v hev1) does not help
- After downgrading to 15.4.1, the same files import without problems

So this looks like a regression in HEVC video handling introduced in 15.5 and still present in 15.6.

Bug is still present in Lightroom 15.6...

LRC 15.6 updated today and STILL video is not working.  

To clarify, some video files now work.  But not the H265 files created by my Galaxy S24.  If I convert those files to H264 they will import and play in LRC 15.6.

But these same files used to import and play just fine in 15.4.1.

Moderators, ​@Sameer K, please merge with the existing bug report:

https://community.adobe.com/bug-reports-674/p-lrc-15-5-video-files-issues-windows-1635342/index1.html

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Adobe has acknowledged this bug introduced into Windows LR 15.5:

https://community.adobe.com/bug-reports-674/p-lrc-15-5-video-files-issues-windows-1635342/index1.html?sort=oldestFirst#comments

While waiting for a fix from Adobe, the only known workaround is to roll back to LR 15.4.

Same problem, 

System & Hardware Setup:

• OS: Windows 11 (fully updated)

• Lightroom Classic Version: 15.5.1

• Processor / GPU: AMD Ryzen 5 5600G with integrated Radeon Vega 7 Graphics (No dedicated GPU installed)

• Media Details: .mov files fail both on import and playback within Lightroom, but play back perfectly fine using native Windows media players and VLC.

Description of the Problem: Since updating to Lightroom Classic v15.5.x, I am unable to import certain .mov files. For previously imported .mov files, Lightroom throws the error message: "There was an error working with the video".

Because these exact files play without any issue in Windows Media Player and external players, the operating system and hardware decoders are fully capable of reading them. This points directly to a regression or compatibility bug in Lightroom Classic’s internal video rendering/import pipeline on Windows 11 systems running on integrated graphics.

Troubleshooting Steps Already Attempted (All Failed to Resolve the Issue):

1. Codec Installation: Installed official HEIF/HEVC Video Extensions from the Microsoft Store and restarted the PC.

2. GPU / Performance Settings: Verified and tested with Graphics Processor disabled, as well as forcing Lightroom Classic via Windows Graphics Settings to run under the "High Performance" profile utilizing the AMD Vega integrated graphics.

3. Driver Updates: Clean-installed the absolute newest AMD Software: Adrenalin Edition driver for the Ryzen 5 5600G.

4. Cache Maintenance: Cleared both the Camera Raw Cache and the Video Cache within Lightroom preferences.

5. Preferences Reset: Performed a complete preferences reset (Shift + Alt launch) to clear out any corrupted post-update configuration files.