Each satellite has their own folder in the blobs folder in your storage location. For the satellite this piece is on that’s v4weeab67sbgvnbwd5z7tweqsqqun7qox2agpbxy44mqqaaaaaaa. The subfolders you see inside there represent the first 2 characters of the piece id. So in your case the folder should be fr. The filename inside that folder is the rest of the piece id with a .sj1 extension. So jgxef52maxhcihttdsbjsez6vpmdqqw6l7zxp2jykasd37pusq.sj1. Path and filenames are in lower case, which is a little annoying since they are logged in upper case. On windows systems this may not matter, but linux/unix systems are case sensitive.
Entire path should be:
[StorjDataLocation]\blobs\v4weeab67sbgvnbwd5z7tweqsqqun7qox2agpbxy44mqqaaaaaaa\fr\jgxef52maxhcihttdsbjsez6vpmdqqw6l7zxp2jykasd37pusq.sj1
Please replace the [StorjDataLocation] part with where your storj data is stored.
Last note: If you use explorer to create the file as @Code_Breaker mentioned. Make sure you have displaying of known file extensions switched on. Otherwise you may unknowingly be naming your file jgxef52maxhcihttdsbjsez6vpmdqqw6l7zxp2jykasd37pusq.sj1.txt.
It may be easier to just run this in CMD:
echo.> [StorjDataLocation]\blobs\v4weeab67sbgvnbwd5z7tweqsqqun7qox2agpbxy44mqqaaaaaaa\fr\jgxef52maxhcihttdsbjsez6vpmdqqw6l7zxp2jykasd37pusq.sj1
Again, please replace the [StorjDataLocation] part with where your storj data is stored.
From the logs I see that you’ve got multiple pieces that have this issue though. So you will need to do this for all of them. You can use https://convertcase.net/ to convert the upper case piece id’s to lower case.