I had to restore from a backup library and had change the names of 300 source files. I am slowly recoonecting them in LR however I accidentally pointed 149 in LR to source file 150 and cannot relink the files properly.
Using your operating system, move the source file to somewhere else. Then an exclamation point icon will appear on file 149 that will allow you to connect it properly. Then move the source file back to where it was.