Im getting a OSX exception randomly, it seems to be file access but its throwing XOJO out rather than giving an exception trap, anyone seen this?

Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000018

VM Regions Near 0x18:
__TEXT 0000000000001000-0000000000617000 [ 6232K] r-x/rwx SM=COW /Applications/app/appnamez.app/Contents/MacOS/appname

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 com.xojo.XojoFramework 0x00862c4f fileNameGetter + 10
1 com.toxic.appname 0x0006a701 FolderItem.Name.Get%s%oi4 + 71

Maybe the FolderItem is Nil when doing

... = fi.Name

Can you show us the relevant source code?

Reboot, whenever apps start crash crashing for bizarre reasons, it’s because the OS has gone a bit wonky.

A common mistake I make is forgetting to check that the object is valid before trying to access properties & functions.

has the item the folder item pointed to been deleted out from under your app ?
that can give some interesting behaviour