I don't think you've given enough information that people could help you with your issue.
What do you mean by they "get lost"?
How are you updating them?
What are you doing when you update them?
How did it work before?
Basically, when i open the file, everything is fine.
1 - Then, the ‘warning’ icon appears on 1 link, then 2, until all links are lost.
2 - I then need to update these links. To do so, I select the links in the links panel, right click, and then click ‘update link’.
3 – then, after a while, links start to get lost again, so back to 1.
I have to mention that I don’t have these issues with all files, but with around 4-5 of them.
Everything was working fine when I was on CS4, it just appeared when I switched to CC.
Hoping this can help understanding…
This links it may help:
Troubleshooting Adobe Applications
What you are describing is links that are "modified," not that are lost, which pretty much means the file timestamp or checksum is changing. Are these links stored on your hard drive or a network share? Is there any sort of backup software or virus scanner at work that might be altering the file in some way?