"At Risk" indicates print quality and success is at risk, but the customer would like to continue with the printing at Best Efforts.
What are Support Structures, Raft Structures, and Support Scarring?
Support Structures are the added part that supports the overhanging structure or bridge structure when slicing the model, which needs to be removed after printing.
Raft Structures are horizontal thin layers of material that are placed. Support Structures & parts are built directly on top of them. They are easily removed with light tools.
Support Scarring are marks left over from where Support Structures were placed. They are easily removed for SLA parts via sanding.
How to remove Support & Raft Structures
Breakaway supports are very simple to remove. You can use gloves and/or pliers for this. You might want a pair of flush cutters.
For FDM parts- Carefully grab the support structures with your hands/tools and pull away from the model.
For SLA parts- Use your flush cutters to snip and break off individual support structures. You'll want to be extra careful in case there are thin walls or features that may break along with it.
How to remove Support Scarring
Support scarring mostly occurs with SLA parts. To remove this scarring, you'll need gloves and sandpapers with varying grits. Start with your lowest/roughest grit, consider starting at 150 grit and working your way up. Carefully sand your surfaces, wiping/rinsing away any extra dust.