Forum Post: ALEs corrupt after upgrades - what are the characteristics of an ALE that will corrupt?

I've seen this many times over the years.   Do an upgrade and the customized ALE lookups become corrupt. Usual process for corrupt ALE's is to restore from backup,  but needless to say after an upgrade, there isn't a good backup to work from since they were just converted.    If it isn't the default lookup for a user you can just delete it and be done, but if it's the default,  often you are stuck and can't get around it.  Sometimes the system offers to let you go to the STANDARD lookup and delete the corrupted one,  but not always.   At which point,  you restore the various files from a system that is clean (no customized ALE's or at least none that are corrupt). Has anyone ever figured out what the characteristics are one an ALE that will corrupt?   I was guessing that maybe there were UDF's involved,  but I just disproved that theory on a test upgrade I am working on right now.