When you generate HTML Help 1.x documentation, you get the following error:
HHC5010: Error: Cannot open "output_path\project_name.chm". Compilation stopped.
There are two possible reassons.
1.CHM file is already open or used. This happens if you open CHM and then try to recompile it.
2.HTML Help 1.x command line compiler hhc.exe cannot compile CHM file to folder whose full path contains folder name starting with dot. If you have that problem, you probably specified output path with folder starting with dot, e.g. "d:\My files\.NET\documentation". You can use dots in folder names but not at the beginning.
•Close CHM file or applications that use it.
•Specify output path without folders starting with dot. Generated CHM file can be placed to such folder later