# Troubleshooting presence of snr.csv Files in Temp folder on NextSeq 500/550 (NCS 4.0.2) Systems running NextSeq Control Software (NCS) v4.0.2 have numerous snr.csv files in the temporary run folder in D:\Illumina\NextSeq Control Software Temp. SNR files have been introduced in the software and are expected to be present in the Temp folder. These are intended to help with signal-to-noise ratio debugging and do not get copied to the output run folder. The local temp folders get automatically deleted by the NextSeq Control Software after a certain time period. Example snr.csv files: * 2021-01-11\_\_19\_07\_54\_32F03D30 GetBestZ Camera 1 Focus Red top surface.snr.csv * 2021-01-11\_\_19\_07\_54\_32F398CF CalculateSignalStd(z\[0]=0.019553, IQData len 18, imax 9, depthOfField 0.018).snr.csv * 2021-01-11\_\_19\_07\_54\_32F4AA19 SafeParabola called by CalculateSignalStd.snr.csv * 2021-01-11\_\_19\_07\_54\_32F6927F SafeParabola called by FindPeakUsingParabolaFit.snr.csv **Troubleshooting steps:** * Leave the files in the temporary run folders as they will be automatically deleted with all remaining files and do not affect sequencing quality or time. * There is no setting to 'switch off' the file generation. \ \ \
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