before and after you change the values in Sample.csv. I suspect one of your columns is changing from a numeric data type to characters.
That is, define masses, blanklabel, and Jpos, then run
X <- read("Samples.csv" masses, blanklabel, Jpos)
summary(X)
# Now edit Samples.csv
X <- read("Samples.csv" masses, blanklabel, Jpos)
summary(X)
Post the output of both summary() calls. Put three back ticks before and after the output, like this
```
output of summary(X)
```