BOM part number edit within .iam not staying applied

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report
I have an assembly file which I am trying to modify the part numbers on. The way I usually do this is by opening the BOM within the .iam and then clicking in the "part number" cell and changing ti to what I what it to be. I also do this for the description cells too. I then press done, hit save and the .iam's and .ipt's of my top level assembly will be updated as per the BOM edits I have made
I am now using Inventor 2018 and I am trying this exact process and it does not seem to be working. It allows me the edit the part number cells and descriptions but does retain these edits after I press done and save. It seems to be a problem related to this particular .iam model as I did a test on a basic assembly and the method described above worked fine?
Any help would be greatly appreciated