Causes
- SD card too slow for the Mission 1 Pro's 240 Mbps bitrate — The GP3 processor writes up to 240 Mbps in 8K60 and 4K240 modes. The camera requires a microSD card rated V30 / UHS-I U3 / Class A2. If your card is slower (V10, Class 4, or an old card that worked fine in a Hero 9/10/11), the write buffer fills up, the camera stalls, and the screen shows "SD ERR". Not all Class 10 cards are equal — different brands have different sustained write speeds, and a card that passes a speed test on a computer can still fail under the Mission 1 Pro's constant bitrate load.
- Card formatted on a computer or used in another device — The Mission 1 Pro expects its microSD card to be formatted in-camera with its preferred exFAT allocation (128 KB clusters). If the card was formatted on a PC/Mac, or previously used in a drone, phone, or another camera, the filesystem layout can confuse the GP3 driver and produce "NO SD" or "CARD ERROR" messages even though the card works elsewhere.
- Corrupted filesystem from an interrupted write — If the Enduro battery dies mid-recording, the card is yanked out while the write light is active, or the camera shuts down from overheating during a write, the filesystem directory can be corrupted. The camera then fails to mount the card, showing "NO SD" or "SD ERR" until the card is repaired or reformatted.
- Dust or debris in the microSD slot — The Mission 1 Pro is waterproof to 20m and frequently used in sand, dirt, and salt spray. Grit on the card's gold contacts or inside the slot interrupts the electrical connection, causing intermittent "SD ERR" messages or the camera to claim no card is present. This is one of the most common causes on action cameras used at the beach or on trails.
- Outdated firmware with 1TB card detection bugs — Early firmware releases (v1.00–v1.20) had known issues detecting high-capacity cards (512GB and 1TB SanDisk/Samsung cards). The camera would show "NO SD" or fail to format the card properly until firmware v1.30, which added support for larger capacity cards and improved the exFAT driver.
- Counterfeit or worn-out card — Fake microSD cards with misreported capacity (e.g., a 16GB card reporting as 512GB) fail the moment writes exceed the real NAND capacity. Cards heavily used in dash cams or security cameras for years can also have worn-out NAND that drops below the write speed the Mission 1 Pro needs, causing random "SD ERR" during recording.
How to Fix
- Back up any recoverable footage first — Before doing anything that could erase data, remove the microSD card and insert it into a computer with a card reader. Copy off any videos you want to keep. If the card is not readable, try a recovery tool such as PhotoRec or SD Card Data Recovery before formatting — formatting will permanently erase everything on the card.
- Re-seat the card and clean the contacts — Power off the camera, open the side door, and remove the microSD card. Inspect the gold contacts for dirt or smudges and wipe them gently with a soft, dry cloth (isopropyl alcohol on a lint-free cloth if heavily soiled — allow to dry fully). Blow out the card slot with canned air or a rocket blower to remove sand and dust. Reinsert the card firmly until it clicks into place, close the door, and power on. A surprising number of "NO SD" errors are simply a card that worked itself loose during a ride or hike.
- Format the card in-camera — With the card inserted, power on the Mission 1 Pro and go to Setup → Format SD Card → OK. In-camera formatting creates the exact exFAT allocation the GP3 processor expects and is the single most effective fix for "SD ERR" and "CARD ERROR". If the camera refuses to format and keeps showing an error, the card or the slot itself is the problem — move to the next steps.
- Format on a computer with the official SD Card Formatter — If the camera won't format the card (common with "NO SD" where the camera can't even mount it), download SD Memory Card Formatter from sdcard.org (free for Mac and Windows). Insert the card via a card reader, launch the tool, select the card, choose "Overwrite Format", and set format type to "EXFAT" (64GB and larger) or "FAT32" (32GB and smaller). Do NOT use the OS's quick format — the official tool properly rebuilds the partition table and clears the write-protect flag that sometimes lingers after corruption.
- Verify your card meets the V30 / UHS-I U3 / A2 requirement — Check the card's label for the V30 logo (a "V" with 30 inside), U3, and A2 ratings. The Mission 1 Pro requires V30 minimum for 8K60 and 4K240. Recommended cards: SanDisk Extreme PRO microSDXC UHS-I V30 A2, Samsung EVO Select microSDXC UHS-I V30 A2, or Lexar Professional Silver Plus microSDXC V30 A2 (all up to 1TB). Note: V60/UHS-II cards are NOT recommended — the Mission 1 Pro has no UHS-II pin row and some UHS-II cards fall back to unreliable UHS-I performance.
- Update the firmware to v1.30 or later — If you're on an early firmware build, update via the GoPro Quik desktop app or the manual SD card method (see the Firmware Update Failed guide on this site for step-by-step instructions). Firmware v1.30 fixed high-capacity card detection and exFAT driver stability. After updating, format the card in-camera once more and test with a short 4K120 clip.
- Run a disk check to rule out filesystem corruption — On a computer, open a terminal (macOS: Disk Utility → First Aid on the card volume; Windows: run "chkdsk X: /f" in Command Prompt as administrator, replacing X with the card's drive letter). This repairs directory errors without erasing files. If chkdsk finds and repairs errors, reinsert the card into the camera — it will often mount correctly again without formatting.
- Test with a different known-good card — Borrow or buy a fresh V30 A2 card from the recommended list. If the new card works flawlessly, your old card is the problem (worn NAND or counterfeit) — replace it. If the new card ALSO shows "SD ERR" or "NO SD" in the camera but works in your computer, the camera's card reader hardware is faulty — contact GoPro Support for warranty service rather than continuing to swap cards.