Microsoft HTML Help .chm file generation double in size and cannot open it (error mk:@MSITStore:)

[beatab1962]

I have been generating  Microsoft HTML Help (.chm file) and Resposive HTML5 successfully with Robohelp 2020.7.46 for my project. The last succesful .chm file that I generated was 98,611KB. After adding quite a bit of content (with new topics, excel files, images), I attempted to generate a .chm however the file was twice the size (196,792KB) and it will not open with error "Cannot open the file: mk:@MSITStore:C:\file). The Responsive HTML5 generation with the same project is successful without any issues. Has anyone seen this error with the .chm file generation?? After I deleted some of the data that I added, I was succesful in getting the file to generate. However, when I try to add new data (not the same as previous add) to the project, it fails again with the same error listed above. Is there a thereshold that I am not aware of??? Has anyone run into this issue?

[Jeff_Coatsworth]

Since CHMs are so antique, I had to google the error message you got - that revealed that the most common issue that causes that error is an offending graphics file. Next in popularity is a bad path/drive location; third is the use of any special characters not in the set of {A,B,C...x,y,z} and underscore; and lastly, a damaged HTML Help Workshop compiler.

[Peter Grainge]

See if this helps. https://community.adobe.com/t5/robohelp-discussions/chm-file-size-almost-doubled/m-p/874182#M35767. It's old but so are CHMs.

Also search on mk:@MSITStore. You will find lots of posts.

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My site www.grainge.org includes many free Authoring and RoboHelp resources that may be of help.

[beatab1962]

Thank you both for your feedback jeff/Peter. Peter, I am using Robohelp 2020 and the majority of the references listed above are for older versions of Robohelp. I have tried creating a new HTML Help Output preset that points to a different output file location (no .chm files in the new location) however it still fails. I have also gone trough all files and images for any special characters but so far I have not found any. I do have many many images in the project and at this point I have tried removing all the images that I added after the last successful build but I'm still encountering the same issue. I have also tried building a .chm file with an earlier version of the project data and that builds just fine so the compiler must be OK. 

[Jeff_Coatsworth]

So it's definitely something you've added since to the project - I suspect you're going to have to brute-force it and add topics back in one at a time (compiling as you go) to find the offending element.

[Peter Grainge]

There will be on of the mk:@MSITStore posts that points to the answer but what @Jeff_Coatsworth has said does seem to be where the problem is.

________________________________________________________

My site www.grainge.org includes many free Authoring and RoboHelp resources that may be of help.