Disable auto-extraction of zip files on windows

Windows explorer comes with integrated support for zip files. While this is good for taking a quick peek into the contents, this is no good for working with zip files. Which means we all use some sophisticated application like 7-zip for managing zip files. Now it happens quite frequently while exploring folders that you try to expand a folder on the left-hand side in the explorer and it will try to load (open) all the zip files existing in the folder.

Functionality to handle this is packaged into zipfldr.dll and this can be disabled simply by un-registering this dll. Run the below at command prompt:

regsvr32 /u zipfldr.dll

Opening CHM files

In the past I have downloaded many CHM files/ebooks but never faced any issues in opening them. One issue I alwasy faced is being not able to open a file present on a network drive, to remedy I used to copy it to my local drive and open.

Recently after copying a file to the local drive also didn't help. When I rightclicked, I see an option to 'unblock' it and then I was able to view the contents. To open CHM file present at any location one need to do a quick registry change:

Locate the key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp\1.x\ItssRestrictions and create a DWORD value called MaxAllowedZone and give it a value of 1

To open CHM present only from a particular location:

Create a string value called UrlAllowList. Give it a value of \\hostname\sharename\;file://; where hostname is the name of your server and sharename is the folder path where the chm files are located. If multiple paths are to be enabled, the value would be \\hostname1\sharename1\;\\hostname2\sharename2\;file://;

The above will allow any CHM in those folders to be opened. Use this format to restrict it to a specific file \\hostname\sharename\yourhelp.chm;file://;

Any CHM except yourhelp.chm in the same folder will continue to be blocked.

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