I know my profile indicates my name is Captiv8r, but I'm known as RoboWizard too.
Unfortuntely there is no way for RoboHelp HTML to be aware of a broken link to something external, such as another .CHM file. Dem's de breaks, I suppose. Not sure of any way past that. Likely this will be a mission of check, double-check and triple-check after you compile.
In thinking about your situation, it seems you might be able to use something that may help with both situations.
I'm referring to something called a "Redirect" topic here. If you have explored this new fad that's catching on (it's called the WWW or World Wide Web) for more than perhaps 10 minutes, you will likely have encountered one of these beasties. Usually you click a link and BAM! You see a page that offers information similar to below:
We're sorry. The page you are linking to has been moved. In 30 seconds you will be automatically moved to our wonderful NEW page. Please update your bookmarks.
Click here if you weren't sent there automatically.
So how does one go about creating such a page?
I'm so happy you asked! (You, um, DID, ask, didn't you? I'm sure you did. )
You edit the HTML code of the page in question. Insert a new meta tag mixed into the tags that are already in the topic. It looks like this:
<meta HTTP-EQUIV=refresh CONTENT="0;URL=CHMFileName.CHM::Path/Topic.HTM">
The problem here is, when dealing with multiple CHM files, you will encounter the behavior you are reporting. The link will likely always want to open in the same Topic pane.
Sorry, don't have any really good answers here. Probably more questions than answers.
Helpful and Handy Links
I did read the Redirect Topic instructions last night but again, it's in a secondary window, not a popup like it was in the .HLP. For a split second, I thought I could use that until I rememberd that the problem with that would be that the secondary window would then have to change the topic in the launching window and close itself. Messy. The person who will be maintaining the content is not a technical person. That's why the popups were great - no worry about targets. Even a local topic in a secondary window wasn't going to be feasible from an ongoing maintenance standpoint due to the HTML editing required for each one.
If I didn't have to link back to the launching window, I'd still have to tweak what you're suggesting to make the redirect topic more flexible, passing in the target as a parameter and making it dynamic since I wouldn't be creating a stub for each of the hundreds of remote topics. I saw an example of that method somewhere last night too (it's in my list of bookmarks, I'm certain) but as it stands right now I think the popup requirement has gone away - same frame is being allowed.
There's a free tool called CHM Link Checker with which you can check the links from one help file to another. You can download this tool from here:
In addition, FAR (which is shareware) can check all the links in a help file.
Have you considered using the KeyHelp ActiveX control for popups? I think this must be one of the few ways to create feature-rich HTML popups whose content is stored externally.