# Mismatched forward and reverse sequence files in Dada2 step

**URL:** https://forum.qiime2.org/t/mismatched-forward-and-reverse-sequence-files-in-dada2-step/14349
**Category:** User Support
**Tags:** dada2, import
**Created:** [April 3, 2020, 5:05pm UTC](https://forum.qiime2.org/t/mismatched-forward-and-reverse-sequence-files-in-dada2-step/14349 "2020-04-03T17:05:15Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![tangmaomao16](https://forum.qiime2.org/letter_avatar_proxy/v4/letter/t/13edae/32.png) [@tangmaomao16](https://forum.qiime2.org/u/tangmaomao16)
#### Post date: [April 3, 2020, 5:05pm UTC](https://forum.qiime2.org/t/mismatched-forward-and-reverse-sequence-files-in-dada2-step/14349/1 "2020-04-03T17:05:15Z")

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I have the sequencing sample names like "H01" and "H01\_1". And I have problem when using  
`qiime dada2 denoise-paired --i-demultiplexed-seqs demux.qza --p-trunc-len-f 290 --p-trunc-len-r 256 --p-trim-left-f 26 --p-trim-left-r 26 --o-representative-se quences rep-seqs-dada2.qza --o-table table-dada2.qza --p-n-threads 0 --o-denoising-stats stats-dada2.qza --verbose`

The error information is  
DADA2 R package version: 1.6.0

1. Filtering Error in filterAndTrim(unfiltsF, filtsF, unfiltsR, filtsR, truncLen = c(truncLenF, :  
These are the errors (up to 5) encountered in individual cores...  
Error in (function (fn, fout, maxN = c(0, 0), truncQ = c(2, 2), truncLen = c(0, :  
Mismatched forward and reverse sequence files: 41704， 46618.  
Error in (function (fn, fout, maxN = c(0, 0), truncQ = c(2, 2), truncLen = c(0, :  
Mismatched forward and reverse sequence files: 46618， 41704.

I unzip the demux.qza file. And I see the files names :  
H01\_0\_L001\_R1\_001.fastq.gz  
H01\_1\_2\_L001\_R1\_001.fastq.gz  
H01\_1\_3\_L001\_R2\_001.fastq.gz  
H01\_1\_L001\_R2\_001.fastq.gz

How can I fix the problem? I cannot change my samples' name because the author want to give such names.

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### Author: ![jwdebelius](https://forum.qiime2.org/user_avatar/forum.qiime2.org/jwdebelius/32/9655_2.png) [@jwdebelius](https://forum.qiime2.org/u/jwdebelius)
#### Post date: [April 3, 2020, 5:38pm UTC](https://forum.qiime2.org/t/mismatched-forward-and-reverse-sequence-files-in-dada2-step/14349/2 "2020-04-03T17:38:00Z")

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Hi @tangmaomao16,

You could try using a `-` instead of an `_` when you import the names with the manifest. However, if the author isnt going to see the analysis IDs, my suggestion would be to rename with a working ID and then return to the original name.

Best,  
Justine

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### Author: ![system](https://forum-qiime2-org.s3.dualstack.us-west-2.amazonaws.com/original/3X/2/1/21af5fe23cb6f4579467c66a9ed94e55274ca7bd.svg) [@system](https://forum.qiime2.org/u/system)
#### Post date: [May 4, 2020, 11:38pm UTC](https://forum.qiime2.org/t/mismatched-forward-and-reverse-sequence-files-in-dada2-step/14349/3 "2020-05-04T23:38:02Z")

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