When you post, please post as much information as possible, including:
The function number: 2756
The complete error text: the collection has been modified, enumering operation could not been executed.
The window affected: main map
What you were doing at the time: 5 days increment, related to life support failure probably.
Conventional or TN start: conventional
Random or Real Stars: real
Is your decimal separator a comma? comma
Is the bug is easy to reproduce, intermittent or a one-off?
If this is a long campaign - say 75 years or longer - let me know the length of the campaign as well: beginning