Last updated: September 1, 2026
When the record button does nothing, or the file that appears will not play, the cause is nearly always the output path, the disk or the chosen format.
Open Settings → Output and confirm the recording path exists and is writable. A folder on a disconnected external drive, a synced cloud folder or a protected system directory can all block writing.
Recording stops the moment the disk fills. Windows controlled folder access can also block the write; add OBS to the allowed applications list if it is enabled.
An MP4 file is only finalised when recording stops cleanly. If the program or the PC crashes, that file is unusable. MKV survives interruptions and remuxes to MP4 in seconds afterwards.
If a hardware encoder was selected and the driver has since changed, recording can fail at start. Switch to x264 temporarily: if it records, update the GPU driver and try the hardware encoder again.
Help → Log Files → Show Log Files opens the folder with the last sessions. The final lines usually name the exact failure, and the log is what the community forums will ask for.