You double-click a video on Windows and instead of playing, Media Player or the Movies & TV app shows "Can't play" and a code: 0xc00d36c4, 0xc00d5212 or 0xc10100be. Search for the code and most of the results come from companies selling video repair software, who have every reason to suggest your file is damaged. It almost never is.

These codes come from Media Foundation, the part of Windows that reads video files, and they have specific official meanings. Taken literally, they tell you what's actually wrong - and the fix is usually free and takes a couple of minutes.

Read the code literally

What each error is actually telling you

0xc00d36c4type not recognised
  • Official: "the byte stream type is unsupported"
  • Windows can't tell what kind of video this is
  • Uncommon file type, wrong extension, or incomplete copy
  • Test in VLC, then convert to MP4
0xc00d5212no decoder
  • Shown as "encoded in a format that's not supported"
  • Windows knows the file but can't decode what's inside
  • Usually HEVC from an iPhone, or AV1
  • Add the decoder, or convert
0xc10100becatch-all
  • Shown as "This file isn't playable"
  • Windows lists three suspects: type, extension, damage
  • Usually one of the other two problems
  • Work through the steps below
Two of the three codes say outright that Windows lacks support for the file. Only one even mentions damage - and lists it last.

#What each code actually means

0xc00d36c4: Windows doesn't recognise the file type

Officially: "The byte stream type of the given URL is unsupported." In plain English, Windows looked at the file, couldn't work out what kind of video it is, and gave up before trying to play anything. Common causes:

  • A file type Windows doesn't support. Windows plays MP4, MOV, MKV, AVI and WMV, but not older or niche types like FLV (Flash video), RMVB (RealMedia) or DAV (Dahua security cameras).
  • An extension that doesn't match the contents. A file renamed from .mkv to .mp4, or a download saved with the wrong extension, trips up Windows' first check.
  • An incomplete file. A copy that stopped part-way, or a download that didn't finish, can leave the start of the file unreadable.

0xc00d5212: Windows can't decode what's inside

Windows shows this one as "This item was encoded in a format that's not supported." The official meaning is that no suitable decoder was found: Windows recognised the file - it knows it's an MP4 or a MOV - but it has no decoder for the video or audio format inside. By far the most common case is an iPhone video. iPhones record in HEVC, and Windows doesn't include an HEVC decoder unless you add one - not even Windows 11. AV1 video is the next most common, and on some PCs so is MPEG-2 video from DVDs and old camcorders.

0xc10100be: the catch-all

Media Player and Movies & TV show "This file isn't playable. That might be because the file type is unsupported, the file extension is incorrect, or the file is corrupt." It's a general message that covers both situations above, plus genuine damage. The steps below tell you which one you have.

#The fix, step by step

  1. Check the file is complete. Compare its size with the original on the phone, camera or download page. If it's smaller, copy or download it again. If you're playing it straight off a phone connected by USB, copy it to the computer first.
  2. Open it in VLC. VLC (free) has its own decoders and doesn't rely on Windows. If it plays, your file is fine and Windows is missing support - carry on to step 3. If VLC fails too, go to step 5.
  3. Find out what's inside. In VLC, open Tools → Codec Information. Or drop the file onto Wave, which lists the formats on its inspect screen without uploading anything.
  4. Add the missing support:
    • HEVC (H.265): install HEVC Video Extensions from the Microsoft Store ($0.99, one-time), keep using VLC, or convert to H.264 - Wave does that in your browser when you turn on Make it play everywhere, and HandBrake does it on the desktop. Is the HEVC extension worth it? walks through the choice.
    • AV1: install the AV1 Video Extension from the Microsoft Store. It's free.
    • MPEG-2: install the MPEG-2 Video Extension from the Microsoft Store, also free.
    • An uncommon file type: convert it to MP4 with H.264 video, which every Windows app plays. Wave does this in your browser for FLV, RMVB, DAV, VOB and dozens of other formats - see all converters.
    • A Windows "N" edition (common in Europe and Korea): these ship without Microsoft's media components, so many formats fail. Install the Media Feature Pack from Settings → Apps → Optional features.
  5. Only if VLC fails too: the file may really be damaged. A recording cut off by a crash or power loss is often missing its index, which the open-source tool untrunc can rebuild using a healthy file recorded on the same device. Check whether you have another copy before paying for anything.

#Advice you can skip

Pages about these errors often recommend things that have nothing to do with them:

  • "Disable copy protection in Windows Media Player." That setting is about ripping audio CDs. It doesn't affect MP4 or MOV files.
  • "Reinstall your USB controllers" or "update your display driver." Those fix hardware problems, not a missing decoder. Copying the file to your computer's own drive is the only USB-related step worth trying.
  • Big codec packs from download sites. Windows needs at most one or two specific extensions, all available from the Microsoft Store. Third-party codec bundles can interfere with the decoders Windows already has.
  • Paid repair software, unless VLC also fails and you have no other copy of the file.

#The short version

  • 0xc00d36c4: Windows doesn't recognise the file type. 0xc00d5212: it can't decode what's inside. 0xc10100be: either of those, or damage.
  • Test in VLC. If it plays there, the file is fine.
  • HEVC: the $0.99 extension, VLC, or convert to H.264. AV1 and MPEG-2: free extensions. Uncommon file types: convert to MP4.
  • Repair software is the last resort, not the first.