When a CHM file that you are trying to access is stored
remotely, e.g. on the network drive or on a remote server, you may also get in
trouble. If the associated security zone is restricted, then CHM files won't be
displayed as well.
Solution:
Modify the ItssRestrictions registry entry to enable a
specific security zone.
Follow these steps:
1. Run 'regedit' command from the command line.
2. Locate and then click the following subkey:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp\1.x\ItssRestrictions
Note: If this registry subkey does not exist, then create
it.
3. Right-click the ItssRestrictions subkey, point to New,
and then click DWORD Value.
4. Type MaxAllowedZone, and then press ENTER.
5. Right-click the MaxAllowedZone value, and then click
Modify.
6. In the Value data box, type a number from 0 and 4, and
then click OK.
The values settings are
0 = My Computer
1 = Local Intranet Zone
2 = Trusted sites Zone
3 = Internet Zone
4 = Restricted Sites Zone
For most CHM files, the value of 1 should be enough to
allow use without opening up access from/to remote CHM files in email/internet
locations.
7. Quit Registry Editor.
Warning Enable only those security zones that you trust.
Do not enable security zones about which you are not sure.