Problems with demultiplexing paired end reads

[Wieneke]

Hi, i imported an old dataset of someone who has already left the university, tahat was originally analysed with another program. The reads ( with barcode in sequence) are in 4 libraries (the lanes?) with each its own fastq forward and reverse file.
The first forward fastqfile looks like this :

I used these commands:
qiime cutadapt demux-paired --i-seqs multiplexed-seqsL26.qza --m-forward-barcodes-file metadata_library26.tsv --m-forward-barcodes-column BarcodeSequence --m-reverse-barcodes-file metadata_library26.tsv --m-reverse-barcodes-column BarcodeSequence --p-error-rate 0 --o-per-sample-sequences demultiplexed-seqsL26.qza --o-untrimmed-sequences untrimmedL26.qza --verbose
And this metadata file
metadata_library26.tsv (474 Bytes)
looking like this

I got this error message:

Is the problem that the reads start with a kind of sequence that seems unique for the library involved? But is not in the barcodes mentioned in the metadatafile?

[Wieneke]

https://forum.qiime2.org/t/problems-with-demultiplexing-dual-indexed-pair-end-sequences-from-miseq-illumina/21571
This seems to contain the answer: Victoria used two metadata files. I used the same column for the forward and reverse reads, as they are the same. Making my metadata file like this:
seemed to do the trick. Atr least it is still processing...