Video uploads fails with the error : Cannot perform ArrayBuffer.prototype.slice on a detached ArrayBuffer

[aryanghugare]

Description

Video uploading error

Reproduction

Steps to reproduce the behavior:

1. Open Cap desktop application
2. select a video for upload in my case it was .mp4 video
3. Attempt to upload the video
4. Observe the upload failure
5. Error appears:
   Cannot perform ArrayBuffer.prototype.slice on a detached ArrayBuffer
   (in the console)

Additional Context

• Cap version:
• Operating system, version:
• Device :

[linear]

CAP-650

[aryanghugare]

Can I work on this ?

[tembo]

This appears to be related to a known issue with the workflow package's ArrayBuffer handling. Several related issues have been reported:

• [Bug] Video processing fails with "detached ArrayBuffer" error #1539 - Video processing fails with "detached ArrayBuffer" error (self-hosted Docker)
• Transcription workflow fails on Docker image with Node 24 #1550 - Transcription workflow fails with the same error (7+ users confirmed)

The root cause is an incompatibility in the workflow package (4.0.1-beta.42) that affects ArrayBuffer operations, particularly during fetch/stream operations. PR #1630 is currently open with a fix that bypasses the problematic workflow package for self-hosted deployments.

To help diagnose your specific case, could you provide:

1. Your Cap desktop app version
2. Your operating system and version
3. Whether this happens with videos you recorded in Cap, or only with imported .mp4 files
4. Whether the video upload was to Cap Cloud (cap.so) or a self-hosted instance

The desktop upload code is in apps/desktop/src-tauri/src/upload.rs and uses multipart S3 uploads via the Rust backend. If you're uploading to a self-hosted instance, the ArrayBuffer error may occur during server-side processing after the upload completes.

If you're using Cap Cloud, this would indicate a different manifestation of the issue on the client side during the upload stream handling.