As some of you have noticed (and reported) we are having trouble with the CHM builds we do of the various MySQL Reference Manuals. This is something that we are looking into, but the reasons and issues behind it are complex. One of the basic reasons if the sheer complexity and size of the documents are now building – there are thousands of files in a standard HTML build, constituting more than 2,500 pages of material. Unfortunately, the final part of the build process, using Microsoft’s own HTML Help Compiler is something we have no control over, and Microsoft no longer support the product. Sometimes it produces a perfectly fine CHM from the source material. Sometimes, using the exact same material, it produces a build that is corrupt in some way. The CHM building process is automatic – I improved it a couple of years ago to be automated as much as possible using a Windows Powershell script that performs nearly all of the work and verifies the build process. But Microsoft’s tool will report a successful build even if the build actually produces a corrupt CHM file. Identifying a corrupt build is difficult; some of the CHM builds open fine on Windows but not in Linux CHM readers, some the other way round, some that don’t work in anything but which reported a completely fine build. We are looking at different ways of addressing the issues, including creating simplified output (removing some of the more esoteric stuff), and releasing CHMs less often that have been manually checked. I’ll let you know the progress, but until then, we’re going to be highlighting the CHM build issue on the download page.