Icaros 3.3.6

A folder of MKV or MP4 files showing nothing but blank white icons is one of the oldest annoyances in Windows.

Icaros fixes it.

It is a free set of shell extensions from the Danish developer Xanashi that teaches File Explorer how to draw a real preview frame for video formats Windows ignores, and there is no paid version waiting behind a button.

Why Your Video Files Show Blank Icons

Windows only knows how to generate thumbnails for a short list of formats it ships support for. Everything else falls back to a generic icon based on the file extension.

A shell extension is a small piece of software that plugs into File Explorer itself and adds a capability it did not have. It is not a program you open and use, it just changes how Explorer behaves from then on.

That distinction matters, because it explains why installing a media player does not fix blank icons. A player knows how to open the file when you double-click it. Explorer still has no idea what the file looks like.

What Icaros Actually Does

Icaros installs two separate parts, and you can turn either one on without the other.

The thumbnail provider grabs a frame from inside the video and hands it to Explorer as the file's picture. It uses FFmpeg underneath, which is the same open-source engine behind most video software on the planet, so the format coverage is enormous.

The property handler fills in the detail columns and the Properties dialog: length, frame width and height, bitrate, codec, title, artist and so on. If you have ever sorted a folder by Length and got an empty column, this is the piece that fixes it.

Both are managed from IcarosConfig, a small control panel that installs alongside them. You open it once, switch on what you want, and then never think about it again.

Which Formats It Covers

For thumbnails, the practical answer is "almost any video file you are likely to have": MKV, MP4, MOV, AVI, FLV, WEBM, M2TS, OGV, RMVB, MXF and a long tail beyond that.

Modern codecs are covered too, including HEVC, AV1 and VVC, plus the newer still-image formats AVIF, HEIC and WEBP.

It also handles a set of formats most thumbnail tools skip entirely: PSD, TGA, DDS, EXR, PDF, SVG, AI, EPS, INDD and comic book archives in CBZ and CBR. That last one is genuinely useful if you keep a comics library and use something like Kindle Comic Converter.

For audio it reads embedded cover art from MKV, FLAC, APE and MPC files, and writes properties for MP3, Opus, WAV, MKA, TAK, TTA and others. So an album folder shows its artwork instead of a row of identical note icons.

If you are not sure what a particular file actually contains, the free online codec finder will tell you in a few seconds, and MediaInfo gives you the full technical breakdown on your desktop.

The Cache Is The Part People Miss

Windows keeps its own thumbnail cache, and Windows also wipes that cache fairly often - after updates, after disk cleanup, sometimes for no visible reason at all. On a large media library that means sitting through thumbnail regeneration again and again.

Icaros keeps its own separate cache that Windows cannot touch. When Explorer loses its copy, Icaros hands the thumbnails straight back at close to instant speed instead of re-decoding every file.

There is also a Cache Indexer, which lets you point Icaros at a folder and pre-generate every thumbnail in advance, before you ever browse there. For anyone with a few thousand video files on a slow drive, this is the single feature worth installing Icaros for.

What Is New In 3.3.6

Version 3.3.6 arrived on 17 June 2026 and is a small maintenance release rather than a rewrite.

• Animated WEBP files now get thumbnails, following FFmpeg adding support for them.
• Comic book archives with UTF-8 filenames inside no longer fail, which mostly affects non-English collections.
• MKV thumbnails now respect rotation, so vertical phone video stops appearing on its side.
• The "Sort title" property in MKV files is now read.
• Some WAV files that showed no properties are fixed, as are older H.264 files that produced green thumbnails.

The previous release, 3.3.5, was the larger one: it added MXF support, more MKV tags, TGA and HDR presets, and fixed HEVC files carrying an alpha layer.

Icaros, SageThumbs Or Media Preview

These three get compared constantly, and the honest answer is that they solve different halves of the same problem.

SageThumbs is the image specialist. It covers 162 image formats including a lot of legacy and scientific ones, but it was last updated in 2017 and does nothing for video.

Media Preview is the closest direct comparison, covering video thumbnails with its own configuration panel, though it has been quiet for years.

Icaros is the one still shipping releases, and it is the only one of the three that also does the properties side. If your problem is video, start here. If your problem is old image formats, SageThumbs alongside it is a sensible pairing, and the two do not fight over the same file types.

For camera RAW and iPhone photos specifically, Microsoft's own Raw Image Extension and HEIF Image Extensions are better maintained than any third-party option.

Installing It Without Breaking Explorer

Shell extensions hook into Explorer, so a careful first run saves trouble later.

1. Run the installer, then open IcarosConfig as administrator. It will not be able to register anything without admin rights.
2. On the Thumbnailing page, pick a preset rather than typing extensions by hand. "Common" suits most people.
3. Click the component name in the Activation panel to switch it from DEACTIVATED to ACTIVATED.
4. Do the same for Properties if you want the detail columns filled in, then set Cache to Enabled (Dynamic).
5. Open a folder of video files. If thumbnails do not appear, sign out and back in so Explorer reloads.

If a file type is already claimed by another extension, Icaros remembers what was there before and puts it back when you deactivate. That is a small piece of engineering courtesy that a lot of shell extensions skip.

There Is A Portable Version

Alongside the installer, Xanashi publishes a plain zip containing the same DLL files.

It is not portable in the usual sense - shell extensions have to be registered with Windows to do anything, so you cannot run this from a USB stick and leave no trace. What the zip gives you is control: you unpack it where you want and register the components yourself with RegSvr32.exe from an administrator command prompt.

On a 64-bit system, register the DLLs from the 64-bit folder. Both the installer and the zip are on the Icaros download page.

Is Icaros Safe To Install

It is freeware, it carries no adware or bundled extras, and the official home is the developer's GitHub repository.

One thing worth being precise about, because plenty of sites get it wrong: Icaros is not open source. The GitHub repository is used for releases and issue tracking, and the source code itself is not published. It is free to use and it is not a black box run by strangers, but "on GitHub" and "open source" are not the same claim.

Because it registers DLL files with the Windows shell, some antivirus tools flag it on first run. That is the behaviour, not a detection of anything malicious, and every file we host is scanned before it goes up.

What You Need To Run It

Icaros runs on Windows Vista, 7, 8, 8.1, 10 and 11, in both 32-bit and 64-bit form. It is one of the few tools in this category that still genuinely supports the older versions rather than just claiming to.

The shell extensions themselves have no dependencies at all. Only IcarosConfig, the control panel, needs the .NET Framework, and the installer handles that for you.

The download is 12.7MB. Memory use is negligible, since thumbnails are generated on demand rather than by a background service sitting in your tray.

Who Should Look Elsewhere

Mac and Linux users are out. This is Windows only, and there is no equivalent port.

If your files will not play at all, thumbnails are the wrong fix. That is a codec problem, and the K-Lite Codec Pack or the HEVC Video Extension is where to start instead.

The tell is simple: if double-clicking the file gives you an error, fix playback first and come back to thumbnails afterwards. Our guide to the HEVC codec for Windows 11 and 10 walks through that side of it, and there is a browser-based online HEVC player for checking a file without installing anything.

And if you want to browse and edit images rather than just see them in Explorer, that is a job Icaros does not attempt.

A real viewer such as IrfanView or XnView covers it properly.

ImageGlass is the lighter option if you only want something quick for paging through a folder.

Quick questions

Where It Fits

Icaros belongs to the small group of tools that make Windows itself better rather than replacing part of it, which is why people install it once and forget it is there.

If you are assembling a full media setup, MKVToolNix handles the container side and FFmpeg covers conversion.

Download Icaros 3.3.6 and see how it handles your files, or tell us how you got on if you have used it before.