Susan has a worksheet with cells hyperlinked to corresponding PDF documents. The hyperlinks work fine until she attempts to perform any type of sorting on the data in the worksheet. After sorting, the hyperlinks are linked to incorrect documents.
This is, apparently, a problem with Excel under some circumstances. According to Microsoft, this occurs if you copy and paste cells containing hyperlinks and then sort the pasted cells. You can find out a bit more about this problem at the following Knowledge Base page:
The problem is, the only solution noted by Microsoft is to manually correct the hyperlinks after doing the sort that created the messed-up links. In other words, there isn’t a real solution.