# Troubleshooting

## General Troubleshooting on Standalone DRAGEN Server

| Failure Type | Actions                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| ------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Software     | <p>- Open the log file <code>./\<AnalysisFolder>/Logs\_Intermediates/pipeline\_trace.txt</code>. This log file displays each pipeline step run by the Nextflow workflow manager software. If a step fails, it is marked as FAILED. Each step generates log files that are stored in step-specific subfolders in the Logs\_Intermediates folder. Review the log files in the relevant Logs\_Intermediates folder for the step to identify potential sources of error.<br>- Open the errors folder <code>./\<AnalysisFolder>/errors</code>. The workflow creates an error file, <code>error\_\<NameOfFailedStep>.json</code>, for each step that failed during analysis. For steps that fail per sample, there is a separately labeled file for each sample that failed each step <code>error\_\<NameOfFailedStep>\_\<SampleIDIfRelevant>.json</code>. These files contain the command and stdout and stderr from the step.</p> |
| Samples      | Open the combined metrics output results file `./<AnalysisFolder>/Results/<PairId>/MetricsOutput.tsv`. If a sample fails an analysis step, the Pair ID that contains the sample shows the failure under `FAILED_STEPS` in the Analysis Status section, and `COMPLETED_ALL_STEPS` shows as False. If available, review the individual log files for the failed steps under `./<AnalysisFolder>/Logs_Intermediates` to identify potential sources of error.                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |

## Sample Sheet Validation Failures

In DRAGEN TruSight Oncology 500 ctDNA Analysis Software, the analysis fails if a sample sheet is invalid. If an invalid sample sheet in suspected, log files can help troubleshoot a failed analysis. Use the following steps to find the log file for the sample sheet:

1. Navigate to the following location `/<analysis_output>/Logs_Intermediates/SamplesheetValidation.`
2. Open the `SamplesheetValidation-.log` file
3. Find a line with the following: `SampleSheetValidationTask:NA:1 exited with return code 1 which has not been declared as a valid return code.`
4. Search for errors in the sample sheet validation log and compare with the guidelines and warnings in [Sample Sheet Requirements](https://help.connected.illumina.com/tso500/dragen-tso-500-ctdna-guides/dragen-tso-500-ctdna-v2.6/run-planning/sample-sheet-requirements) and the following tables.

### General troubleshooting for a failed sample sheet:

| Failure Type                                         | Action                                                                                                                                                                                                                |
| ---------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Sample Sheet not found                               | Verify that `SampleSheet.csv` is present at the top level of the run folder with the name "SampleSheet.csv". If the sample sheet is in a different location, supply the sample sheet using the `--sampleSheet` option |
| Indexes are not valid for the sequencer and/or assay | See Valid indexes for assay and instrument combinations for correct indexes for the sequencer and assay.                                                                                                              |
| Sample Sheet is not in v2 format                     | Verify that the format of the sample sheet is v2. v1 sample sheet is not compatible with DRAGEN TruSight Oncology 500 ctDNA Analysis Software.                                                                        |
| Analysis does not run                                | Verify the analysis starts from the run folder, and BCLs or FASTQs are in the correct locations as outlined in Starting From BCL Files and Starting From FASTQ Files respectively.                                    |

### Valid indexes for assay and index combinations:

| Assay            | Index Set ID                      |
| ---------------- | --------------------------------- |
| TSO 500 ctDNA    | <ul><li>UP1-UP16</li></ul>        |
| TSO 500 ctDNA v2 | <ul><li>UDP0001–UDP0192</li></ul> |

### Troubleshooting BCL issues:

| Failure Type                           | Action                                                                                                                                                                                                                                                                      |
| -------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Lane Column without Values             | Ensure that the column is completed. If lane is not applicable to the run, delete the column.                                                                                                                                                                               |
| Format of v2 sample sheet is incorrect | Verify that the sections and fields are present in the sample sheet and follow the individual rules in [Sample Sheet Requirements](https://help.connected.illumina.com/tso500/dragen-tso-500-ctdna-guides/dragen-tso-500-ctdna-v2.6/run-planning/sample-sheet-requirements) |

### Troubleshooting FASTQs issues:

| Failure Type               | Action                                                                                                                                                                                                                                                                                                     |
| -------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Unique sample IDs          | Verify that the Sample\_IDs are unique in the sample sheet.                                                                                                                                                                                                                                                |
| Incorrect folder structure | Verify that the FASTQ files are in the correct structure. Refer to [Starting From FASTQ Files](https://help.connected.illumina.com/tso500/dragen-tso-500-ctdna-guides/launching-analysis/analysis-launch-on-standalone-dragen-server/command-line-options#starting-from-fastq-files) for more information. |
| Invalid FASTQ input files  | If the FASTQs are invalid, start TSO 500 ctDNA analysis from BCL files.                                                                                                                                                                                                                                    |

## Other Troubleshooting Tips

| Failure Type                                                                                      | Action                                                                                                                                                                                                                                                                                                                                                                   |
| ------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| The output file directory contains information from previous analyses                             | <p>If this issue is seen: specify a new target output folder and repeat analysis<br><br>To prevent this issue: specify an empty directory before starting analysis</p>                                                                                                                                                                                                   |
| Single exon (single probe) genes are still reported in the CNV VCF file, but not the CNV TSV file | <p>No action needed; software is working as expected.</p><p>Currently all single probe genes are not emitted to the Copy Number Variants section of our CombinedVariantOutput.tsv. However, you can still find these events in the cnv.vcf.gz.</p><p>Due to the single probe nature, accurate CNV calling has not been validated and as such they are emitted as REF</p> |
| Testing of cell lines, contrived samples and commercial controls does not return expected results | Review recommendations for using these samples types [here](https://help.connected.illumina.com/tso500/performance-testing/contrived-and-cell-line-sample-considerations).                                                                                                                                                                                               |

## Troubleshooting on ICA

In addition to TSO 500 managed sample sheet validations, ICA managed TSO 500 errors include the following:

| Error                                                                                                   | Description                                                                                                                                                                                                                                                                                                                                    |
| ------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Failure type: ValueError: Could not find pipeline ID for app BCLConvert in sample sheet SampleSheet.csv | Action: Ensure StartsFromFastq field is in the \[TSO500L\_Settings] section, and it is not present in the \[BCLConvert\_Settings] Section. Refer to [Sample Sheet Requirements](https://help.connected.illumina.com/tso500/dragen-tso-500-ctdna-guides/dragen-tso-500-ctdna-v2.6/run-planning/sample-sheet-requirements) for more information. |
