Error: "Create session error : X3 engine error: <folder path>\FIL\ACLASSE.fde : File Non-existent"


There are various possibilities including a corrupt ACLASSE table or an outstanding folder validation 


1. Try to validate the ACLASSE table through Development > Data and Parameters > tables

2. Test

if the above fix fails, perform folder validation 

Nb. This can time time depending with size of folder.