I/O error writing .dta file while merging

[James Park]

While I was merging two large files, Stata displayed an error message that reads

I/O error writing .dta file
Usually such I/O errors are caused by the disk or
file system being full.

I wasn't saving the file. I was merging. Also, I was merging one data in F drive, another data in C drive. Both F and C drive have 1TB of free space. The main file is 93.1GB, and the other file is merely 1GB. Then why am I seeing this error?

[Sarah Edgington]

Are the files you're merging sorted on your merge variables? Looking at the merge.ado file there's a place where it saves a tempfile if the using data isn't sorted. There may also be other instances where merge saves a tempfile. You could try sorting your using data and see if that fixes the problem. If not I would verify that the directory where Stata writes tempfiles has sufficient space to save your data.