Hope someone can help

I have had problems with the item library disappearing, but i've managed to get them back but have now got an Object I/O "C:/user/Dave/Appdata/Local/Autodesk/fabrication2018/Cadmep/cadtakeoff.map" Error 4 - unable to open file

I can retry or cancel 

If i retry the error stays up, if i cancel the item is added.

This is occurring if i modify an item or amend an existing item.

The duct is modified but keep getting the error panel is very annoying.

can anyone help please?

Cheers