If you're new to the F@H Project, have a read of this topic for a quick overview: Welcome To The F@H Support Forum
1 - Problematic Hardware
Sometimes a WU assigned to your F@H Client is a good one but due to some specific hardware problem on your system, it cannot be folded correctly. Thus it has returned an error. This issue has to be fixed on the Donors system in order for the system to continue folding without issues (more details below).
2 - Bad WU
Sometimes a WU assigned to your F@H Client is a bad one but due to the statistical nature of folding. The F@H Team tries to keep a very low error rate such as:
- <1% of the Project in release (i.e. full F@H)
- Between 1% or 2% (inclusive) for advanced (pre-release testing by Public Donors)
- Higher than 2 (inclusive) for earlier testing (Beta testers and internal testers)
Note: The use of <client-type v='advanced'/> increases your probability of getting a bad WU since you will have access to pre-release WUs.