Cross references between books sometimes point to the wrong place in PDF output

[Oscar_the_GamingWriter]

Hello FM community,

Environment: I'm using FM2019 unstructured creating multiple (25) books for PDF only output.

I posted a few weeks ago about a 25 book project that needs be heavily cross-referenced. With help from this community, I was able to start my project. I am methodically going thru all the books, and just finished #7 (of 25).

This morning, I just noticed that many of my cross references are pointing to the wrong place. I've recreated these x-refs, confirmed that are correct, and it still seems to happen.

Has anyone ever experienced x-refs that go to the wrong place? 

I know that when creating the book PDF both books being connected need to be open. I'm doing this. I'm wondering if perhaps:

Perhaps I need to have all book FM files open? Up to now, I simply open the book the reference is going to, but not the actual fm file within that book. But then why do some x-refs work, and not others?

Very perplexing. Any comments are appreciated. 

[Jeff_Coatsworth]

I'm not clear how you're making an xref to a .book file instead of to someplace in a .fm file. I've never tried to make a book reference - I always point to either a paragraph tag or a cross-reference marker.

[Oscar_the_GamingWriter]

The x-ref is going from an FM file in book1 to an FM file in book2.

I know that for this to work, both books need to be open, but the FM file I'm linking to in book2 is not open.

It's works sometimes. And other times, the x-ref simply goes somewhere else - not too far away, but not where I directed it to. Thanks. I've never had a problem like this. Very, very odd.

[Jeff_Coatsworth]

You need the .fm files open in both books, not the .book files themselves. I suspect you may be bumping into a secret limit on the absolute length of the path+filename that FM can support in xrefs - it's about 30-50 or so characters. Have a look at one that failed & one that works - look at the total length of the directory path+filename of each. I was seeing the same thing happen when I imported my FM content in RH - some links would work & some would fail - all on the same page. It would behave correctly in FM while authoring, but when sent to RH, the links were broken. Took some digging, but when I shortened the total path length (I didn't want to change the filename because I already had tons of xrefs to them) it worked.

[Oscar_the_GamingWriter]

Actually, I misspoke, I do have both sending and receiving FM files open.

And I do see a direct relationship between # of characters and working/non-working references. Thanks for the heads up Jeff. I'm going to proceed and test this thoroughly. 

Is there a workaround to this? or do I simply figure out a way to shorten the reference? 

[Jeff_Coatsworth]

Unfortunately the workaround is to make everything shorter. In my case I was able to preserve the relative position between all my FM books and docs (because I had everything all under one folder, with many branches under that one folder) and just shortening the path to that one folder did the trick. Depending on your file/folder structure, YMMV.