Opening a CHM file produces navigation to the webpage was canceled

Question

I am trying to open a  chm file   I downloaded the source  extracted it  and double clicked on Waffle chm and clicked  Open  but no matter what element in the chm file I click  I get the message   Navigation to the webpage was canceled    What you can try   Retype the address        What s going on here

User · Answer

Moving to local folder is the quickest solution, nothing else worked for me esp because I was not admin on my system (can't edit registery etc), which is a typical case in a work environment.

Create a folder in C:\help drive, lets call it help and copy the files there and open.

Do not copy to mydocuments or anywhere else, those locations are usually on network drive in office setup and will not work.

User · Answer

other way is to use different third party software   This link shows more third party software to view chm files      I tried with SumatraPDF and it work fine

User · Answer

Go to Start  Type regsvr32 hhctrl ocx  You should get a success message like        DllRegisterServer in hhctrl ocx succeeded     Now try to open your CHM file again

User · Answer

unblocking  the file fixes the problem   Screenshot

User · Answer

I fixed this programmatically in my software  using C   Builder     Before I assign the CHM help file  Application- gt HelpFile   HelpFileName  I check to see if it contains the  Zone Identifier  stream  and when it does  I simply remove it   String ZIStream HelpFileName     Zone Identifier      if  FileExists ZIStream         DeleteFile ZIStream

User · Answer

In addition to Eric Leschinski s answer  and because this is stackoverflow  a programmatical solution   Windows uses hidden file forks to mark content as  downloaded   Truncating these unblocks the file  The name of the stream used for CHM s is  Zone Identifier   One can access streams by appending  streamname when opening the file   keep backups the first time  in case your RTL messes that up    In Delphi it would look like this   var f   file  begin  writeln  unblocking   s    assignfile f  some chm Zone Identifier     rewrite f 1    truncate f    closefile f   end    I m told that on non forked filesystems  like FAT32  there are hidden files  but I haven t gotten to the bottom of that yet   P s  Delphi s DeleteFile   should also recognize forks

User · Answer

Win 8 x64   just move it to another folder or rename your folder  in my case  my folder was  c     avoid to use symbol on folder name  name it with letter   done

User · Answer

The definitive solution is to allow the InfoTech protocol to work in the intranet zone   Add the following value to the registry and the problem should be solved    HKEY LOCAL MACHINE SOFTWARE Microsoft HTMLHelp 1 x ItssRestrictions   MaxAllowedZone  dword 00000001   More info here  http   support microsoft com kb 896054

User · Answer

Summary  Microsoft Security Updates 896358  amp  840315 block display of CHM file contents when opened from a network drive  or a UNC path    This is Windows  attempt to stop attack vectors for viruses malware from infecting your computer and has blocked out the  chm file that draw data over the  InfoTech  protocol  which this chm file uses   Microsoft s summary of the problem   http   support microsoft com kb 896054  Solutions   If you are using Windows Server 2008  Windows 7  windows has created a quick fix   Right click the chm file  and you will get the  yourfile chm Properties  dialog box  at the bottom  a button called  Unblock  appears   Click Unblock and press OK  and try to open the chm file again  it works correctly   This option is not available for earlier versions of Windows before WindowsXP  SP3      Solve the problem by moving your chm file OFF the network drive   You may be unaware you are using a network drive  double check now  Right click your  chm file  click properties and look at the  location  field   If it starts with two backslashes like this    epicserver blah   then you are using a networked drive   So to fix it  Copy the chm file  and paste it into a local drive   like C   or E    Then try to reopen the chm file  windows does not freak out  Last resort  if you can t copy move the file off the networked drive   If you must open it where it sits  and you are using a lesser version of windows like XP  Vista  ME or other  you will have to manually tell Windows not to freak out over this  chm file   HHReg  HTML Help Registration Utility  Utility Automates this Task   Basically you download the HHReg utility  load your  chm file  press OK  and it will create the necessary registry keys to tell Windows not to block it   For more info   http   www winhelponline com blog fix-cannot-view-chm-files-network-xp-2003-vista    Windows 8 or 10   --   Upgrade to Windows XP

User · Answer

There are apparently different levels of authentication  Most articles I read tell you to set the MaxAllowedZone to  1  which means that local machine zone and intranet zone are allowed but  4  allows access for  all  zones   For more info  read this article  https   support microsoft com en-us kb 892675  This is how my registry looks  I wasn t sure it would work with the wild cards but it seems to work for me    Windows Registry Editor Version 5 00   HKEY LOCAL MACHINE SOFTWARE Microsoft HTMLHelp    HKEY LOCAL MACHINE SOFTWARE Microsoft HTMLHelp 1 x    HKEY LOCAL MACHINE SOFTWARE Microsoft HTMLHelp 1 x ItssRestrictions   MaxAllowedZone  dword 00000004   HKEY LOCAL MACHINE SOFTWARE Microsoft HTMLHelp 1 x ItssRestrictions   UrlAllowList        lt network path root gt       lt network path root gt      ies-inc local http   www   http     https   www   https         As an additional note  weirdly the  UrlAllowList  key was required to make this work on another PC but not my test one  It s probably not required at all but when I added it  it fixed the problem  The user may have not closed the original file or something like that  So just a consideration  I suggest try the least and test it  then add if needed  Once you confirm  you can deploy if needed  Good Luck   Edit  P S  Another method that worked was mapping the path to the network locally by using mklink  d  symbolic linking in Windows 7 or newer  but mapping a network drive letter  Z  for testing  did not work  Just food for thought and I did not have to  Unblock  any files  Also the accepted  Solution  did not resolve the issue for me

[windows] Opening a CHM file produces: "navigation to the webpage was canceled"

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