I’m building an asset bundle out of a single asset, an FBX. This is a complicated FBX, 200 megabytes and around 2500 submeshes (but only a few textures); it takes about 5 minutes for Unity to import it at first startup. In the end it's 28 files that are being built into the AssetBundle, with the textures and materials. But it takes about an hour to build that into an asset bundle, and I’m not compressing it at all! I’m building for Windows Standalone 64-bit, which is what my project is set to, so it doesn’t need to re-import to build the bundle. Code (CSharp): BuildPipeline.BuildAssetBundles(“Asset/AssetBundleOutput”, buildMap, BuildAssetBundleOptions.UncompressedAssetBundle, BuildTarget.StandaloneWindows64); So why does it take so long? The progress bar doesn’t say anything but “Building AssetBundles”; Windows 10 says Unity is using around 8.5% of my CPU, it’s not accessing the hard disk in a noticeable way, nothing else is happening, it’s only using 1GB of my 64GB memory, and I’ve got a fairly powerful CPU (i7-6900K at 3.2ghz). Any tips for speeding this up? I’ve tried setting Unity to “realtime” priority in Windows, didn’t seem to help.