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Why sometimes, I can't view the content of the chm files which I downloaded? It gives me something like this when I open it.

The address is not valid

Most likely causes: There might be a typing error in the address. If you clicked on a link, it may be out of date. What you can try: Retype the address.

 Go back to the previous page.
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migrated from stackoverflow.com Dec 26 '10 at 17:48

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4 Answers

up vote 9 down vote accepted

Go To properties of file and Unblock it. Downloaded CHM files are blocked by default by Windows due to security.

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Thanks for this, I've met this sometimes when I used to use windows. –  nXqd Dec 26 '10 at 17:56
Thanks a lot for this valuable help.... –  Kugathasan Abimaran Jan 31 '11 at 15:14
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Right click on the file, select properties, click the "unblock" button. Screenshot here:

Vista Blocked File Protection Control

This file came from another computer and might be blocked to help protect this computer.

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Sometimes if path to your CHM file is too long, a file cannot be opened properly. To check if this is a reason, just copy your file in some root folder (for example C:\ or D:\ or something similar).

Edit: The other reason is if file is blocked and it should be unblocked, of course.

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This is security feature.

Solutions are:

  1. You can unblock by right click on the file and choose properties. in the bottom , click unblock and apply the changes.

  2. Double-click the .chm file. In the Open File-Security Warning dialog box, click to clear the Always ask before opening this file check box. Click Open.

  3. Microsoft not much help; if their 'unblock' does not work or is missing- try the following: This worked for me in XP (not sure about Windows 7) Go to Google, search for UniExtract otherwise known as Universal Extractor ---it was free last time i looked, download, install, set to include context menus. Then right click a .chm file and the context menu choices should appear if installation was successful ---left click on extract to subdirectory, this means that the file will be extracted to a new folder same name as the .chm file. Open folder and your goodie file should be there as an htm, select the initial TOC, table of contents, left click it and it should open in your default browser, use "next" key buttons to scroll thru to your next page, so on and on

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