> For the complete documentation index, see [llms.txt](https://knowledge.illumina.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://knowledge.illumina.com/instrumentation/nextseq-1000-2000/instrumentation-nextseq-1000-2000-troubleshooting-list/000005170.md).
# Pre run check failure due to "I/O error" on the NextSeq 1000/2000
The "I/O error" occurs during the DRY checks of the pre-run checks on the NextSeq 1000/2000.
To troubleshoot:
1. Power cycle instrument and re-attempt run setup with same consumables. Search for Knowledge Article: **How to power cycle the NextSeq 1000/2000**.
2. If error persists after power cycling, remove cartridge from the instrument and perform system checks. Search for Knowledge Article: **System Checks for the NextSeq 1000/2000**.
3. Collect the following files from the instrument:
1. System check results (located in /usr/local/illumina/systemcheck)
2. Run set up logs (located in /usr/local/Illumina/Runs/Setup/\[Date\_Time]).
4. Provide the collected files in Step 3 to [Illumina Technical Support](https://www.illumina.com/company/contact-us.html#/) for evaluation and next steps.
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| *For any feedback or questions regarding this article (Illumina Knowledge Article #5170), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000005170%20-%20Instrumentation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |
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