Error 8 occurs when there has been an arc within the cuvette during application of the electrical program. The program was begun but was interrupted because too much current was detected. Efficiency may be lower than expected due to the incomplete delivery; however, the cells can still be plated for analysis. This generally occurs because the conductivity of the solution was outside of accepted limits – this can happen if the media was not completely aspirated before resuspending, too much solution (or an inappropriate solution) was used or an inappropriate cuvette was used. It is also possible that the device is defective. To check this, we suggest applying the program to a sample with Nucleofector™ Solution alone (i.e. no cells and no DNA) and repeating this 5-10 times (to avoid overheating wait 1 min between the pulses). If this combination also produces an error 8 (or any other error) the device will have to be returned for a full diagnostic analysis. However, if you don't get error messages in samples without cells and DNA we can exclude that the device is defective.