# ros2 bag play: Could not open bag 'my_bag' - storage plugin 'mcap' not found

- **ID:** `ros2/rosbag2-play-missing-storage-plugin`
- **Domain:** ros2
- **Category:** resource_error
- **Verification:** ai_generated
- **Fix Rate:** 95%

## Root Cause

The rosbag2 storage plugin for the bag format (e.g., mcap, sqlite3) is not installed, so the bag file cannot be read.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| Humble | active | — | — |
| Iron | active | — | — |
| Jazzy | active | — | — |
| Rolling | active | — | — |

## Workarounds

1. **Install the missing storage plugin using apt.** (95% success)
   ```
   Install the missing storage plugin using apt.
   ```
2. **Check which storage plugins are available and use a supported format.** (90% success)
   ```
   Check which storage plugins are available and use a supported format.
   ```
3. **Re-record the bag with a known working storage plugin.** (85% success)
   ```
   Re-record the bag with a known working storage plugin.
   ```

## Dead Ends

- **Reinstalling rosbag2 package without the storage plugin** — rosbag2 core doesn't include all storage plugins; they must be installed separately. (70% fail)
- **Converting the bag file manually with a hex editor** — Bag files are structured binary formats; manual editing corrupts them. (90% fail)
- **Setting ROS_DOMAIN_ID to a different value** — Domain ID affects discovery, not storage plugin loading. (20% fail)