Error: Failed to open [Covariate File]

Question

[Mahan]

Hi Everyone! I'm doing a GWAS analysis for SNP. I'm using:

plink --file mydata --covar c.txt --covar-name AGE,BMI-SMOKE,ALC 

But I'm getting this error:

Failed to open [Covariate.txt]

Any suggestions? I have checked the file name and its spelled correctly!