OBS "No Space Left on Device" Error - Fix

OBS "No Space Left on Device": Fix

Your recording stops mid-session and OBS reports No space left on device. You check the drive and there are eighty gigabytes free.

The message is accurate but imprecise. What OBS is reporting is that the operating system refused the next write. A genuinely full disk is one reason for that refusal. It is not the only one, and on a drive with obvious free space it is not even the most likely one.

The single most useful diagnostic is when it failed. That timing narrows the cause faster than anything you can check in settings.

Step 1: Move the Recording Off Your System Drive

If OBS is writing to C:\\ on Windows or your startup disk on Mac, that drive is also holding the operating system, your applications, virtual memory, and temporary files. Video is the largest thing most people write, and system drives are the smallest volume in most machines.

1. Open Settings > Output.
2. In Simple mode, look at Recording Path. In Advanced mode, open the Recording tab and look there.
3. Click Browse and choose a folder on a secondary internal drive or a large external one.
4. Create a dedicated folder — D:\\OBS Recordings — rather than writing to the drive root.
5. Click Apply.

Leave meaningful headroom. A system drive running below about 10% free will also slow down and can cause dropped frames well before it causes this error.

Step 2: The FAT32 4 GB Wall

This is the cause behind almost every "but the drive is not full" case.

FAT32 cannot store a single file larger than 4 GB. Not by policy — the format has no way to express a larger size. The moment your recording crosses that boundary the write is refused, and OBS surfaces it as a space error because that is what the operating system returned.

FAT32 is still the default format on most USB flash drives, many SD cards, and a good number of external drives sold pre-formatted for maximum compatibility. So the drive can report 500 GB free and still refuse a 4.1 GB file.

The signature is the timing. At common recording settings, 4 GB arrives somewhere between fifteen and twenty-five minutes in, and it will happen at almost exactly the same point every time. If your recordings die at a consistent duration rather than a consistent time of day, this is your cause.

How to check the format:

• Windows: open File Explorer, right-click the drive, choose Properties, and read the File system line.
• Mac: open Disk Utility, select the volume, and read the format under its name.

How to fix it. Reformat to a modern file system. This erases the drive, so move anything you need off it first.

On Windows: right-click the drive, choose Format, set File system to exFAT or NTFS, and click Start. On Mac: Disk Utility > Erase, and choose ExFAT or APFS.

Pick exFAT if the drive moves between machines. It is slightly less resilient to improper ejection than NTFS, so eject it properly.

Step 3: Stop Producing Files This Large

If the drive really is filling up, the recordings are bigger than they need to be. Most people are recording at a quality level well beyond what their footage requires.

Rough sizes per hour at 1080p:

These vary with content — a static slide deck compresses to a fraction of a fast-moving game — but the ratios hold.

If you are on CQP: open Settings > Output > Recording and check the CQ Level. Lower numbers mean higher quality and larger files. A CQ Level of 14 or 15 produces enormous files for footage that is mostly static UI. Raise it to 20–23. For screen recording, where most of the frame does not change between frames, the difference is not visible at normal viewing size and the file is a fraction of the size.

Two other settings worth checking:

• Frame rate. 60 fps roughly doubles the data of 30 fps. Screen recordings of software rarely benefit — 60fps vs 30fps Screen Recording covers when it is worth it.
• Resolution. If you are recording a 4K display and publishing at 1080p, set Output (Scaled) Resolution in Settings > Video to 1920×1080 and record at the size you will actually use.

OBS Recording File Too Large: How to Reduce Size goes further on this.

Step 4: The Refusals That Are Not About Space

If the failure is instant, or only happens in one location, the file system is refusing you for a reason unrelated to capacity.

Cloud-synced folders. Recording directly into OneDrive, Dropbox, iCloud Drive or Google Drive is a reliable way to produce this error unpredictably. The sync client locks and uploads the file while OBS is still writing it, and on OneDrive with Files On-Demand the local free space reported can be wrong entirely. Record to a local folder and move the file afterwards.

Permissions. Folders inside Program Files, Windows, or the root of the system drive are not writable by standard user accounts. Record into your user directory — C:\\Users\\<you>\\Videos or ~/Movies — instead.

Network and NAS paths. SMB shares report free space for the whole volume, while your account may have a much smaller quota. The share can also drop briefly and return, which OBS sees as a failed write. Record locally and copy across afterwards.

A drive that is full of things you cannot see. Windows System Restore and Previous Versions snapshots consume space invisibly on some configurations, as does a large hibernation file. If a drive reports far less free space than the files on it account for, run Disk Cleanup and check restore point allocation.

Replay buffer. A generous replay buffer holds video in RAM and flushes it on save. If it is enabled with a long maximum replay time, it contributes to disk pressure at unpredictable moments. Settings > Output > Replay Buffer.

Recover the Recording You Just Lost

Before rerunning anything, check whether the interrupted file is salvageable.

If you were recording to MKV, it very likely is. MKV is written so that a file cut short mid-write remains playable up to the interruption. Open File > Remux Recordings in OBS and convert it to MP4 — that rewrites the container without re-encoding, so it is fast and lossless.

If you were recording to MP4, it likely is not. MP4 writes its index at the end of the file, and a file that never reached the end has no index. This is the single best argument for recording in MKV and remuxing afterwards, which is what OBS MKV vs MP4 recommends.

The Storage Cost Nobody Budgets For

Work through the fixes above and the error goes away, but the underlying arithmetic does not. A raw OBS capture is an intermediate file. You record 12 GB, edit it, export a second file, and keep both because deleting the source before the client has approved the cut is how people lose work. Do that weekly and a terabyte disappears inside a year.

That is a reasonable trade if you are doing real post-production, where the high-bitrate source genuinely matters. It is pure overhead if your edit consists of adding zooms so the UI is readable on a phone.

Cubix Capture applies the zooms, cursor smoothing and framing during capture, so what you get when you stop is the finished file rather than a source to edit. One file per video instead of two, and no CQP value to get wrong. It runs on Windows and Mac, with a free Starter plan and no account required.

Keep Reading

• OBS Recording File Too Large: How to Reduce Size for the settings that drive file size.
• OBS MKV vs MP4: Which Should You Use? on which container survives an interruption.
• OBS Can't Find Recording: Where Are OBS Files Saved? if you changed the path and lost track of the output.
• OBS "An Error Occurred While Starting the Output": Fix if recording will not start at all.