# An error was encountered while running DADA2 in R (return code 1); Error in err\[c(1, 6, 11, 16), \] \<- 1

**URL:** https://forum.qiime2.org/t/an-error-was-encountered-while-running-dada2-in-r-return-code-1-error-in-err-c-1-6-11-16-1/11311
**Category:** User Support
**Tags:** dada2
**Created:** [August 29, 2019, 2:21pm UTC](https://forum.qiime2.org/t/an-error-was-encountered-while-running-dada2-in-r-return-code-1-error-in-err-c-1-6-11-16-1/11311 "2019-08-29T14:21:49Z")
**Posts on this page:** 1
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### Author: ![thermokarst](https://forum.qiime2.org/letter_avatar_proxy/v4/letter/t/8e7dd6/32.png) [@thermokarst](https://forum.qiime2.org/u/thermokarst)
#### Post date: [August 30, 2019, 3:54am UTC](https://forum.qiime2.org/t/an-error-was-encountered-while-running-dada2-in-r-return-code-1-error-in-err-c-1-6-11-16-1/11311/5 "2019-08-30T03:54:02Z")

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I believe the error is stemming from an issue related to the _characteristics_ of the reads (I seem to recall this has to do with the case when many (all?) sequences are unique). See this thread for more detail:

> [@Error running DADA2 in 454 data](https://forum.qiime2.org/t/error-running-dada2-in-454-data/8051/2):
>
> I found a similar error on the DADA2 error tracker: [https://github.com/benjjneb/dada2/issues/614](https://github.com/benjjneb/dada2/issues/614) Maybe you can try some of the checks suggested in that thread? You will already have a copy of DADA2 (and R) on hand in your QIIME 2 env. FWIW, in the linked issue it sounds like the reason this error happened is because all of the reads in the data were unique - no groupings of reads were identified.

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