Yes, you can use other segments to include or exclude from the one your are building.
Why is this then? A simple case could be that you don't want to include any contacts that's already in another segments, or on the opposite way you want to include all contacts from a specific segment.
Creating an endless loop
When encountering this error inside of your segment, here's probably the reason why:
You've selected two (or more) segments that are set to include contacts from each other. This means:
- Segment A will import contacts from Segment B
- Those contacts are added into Segment A
- Segment B will then start the import from Segment A which in terms brings you back to Segment A starting it's import again.
Congratulations, you almost created an endless loop.
The solution might vary depending on what you are trying to achieve. If you want the same contacts as another segment, use the same filters in the one you are building.