I am trying to run a BLAST command on macOS:

blastp -query /Users/shalini/Desktop/shalini/project/unmodelled_fasta/AAA18895.fasta -outfmt "7 sacc qcovs pident ppos evalue" -db=/Users/shalini/Downloads/nr -out=/Users/shalini/Desktop/shalini/project/blast_resultnr

After running for over an hour, I am getting the following error message:

Error memory mapping:/Users/shalini/Downloads/nr.79.phr openedFilesCount=251 threadID=0 BLAST Database error: Cannot memory map /Users/shalini/Downloads/nr.79.phr. Number of files opened: 251

I have built the NR database which is made up of 114 .phr, .pin, .psq, and .pog files.

Can anyone help me with this issue?

The error message suggests that there are too many files open for the BLAST command to run successfully. You can try increasing the maximum number of open files allowed by your system by running the following command in the terminal:

ulimit -n 2048

This will set the maximum number of open files to 2048. You can adjust this number as needed. Then, try running your BLAST command again.