once / when

[sh.hazeri]

Which one is more accurate and common ?

- I will email again once it completes
- I will email again when it completes

[philadelphia]

*Not a teacher

When is suitable for future tenses.

[IHIVG]

Which one is more accurate and common ?

- I will email again once it completes
- I will email again when it completes

The 'it' is not clear. Once what completes? If you mean an e-mail, it can't complete, but it can be completed. You can't refer to the e-mail as 'it,' because it functions as a verb in your sentence.

Do you mean: "I will e-mail you again [once I've finished/when I finish my letter/writing/checking X, etc.]
I will send you an e-mail again [once/when it's finished/completed.]

However, unless the 'it' refers to something other than e-mail, the parts about completion seem unnecessary.

[kfredson]

Which one is more accurate and common ?

- I will email again once it completes
- I will email again when it completes

I would say that "once" and "when" are interchangeable in such a sentence. When I search on google for "once I am done" I get only one-tenth as many hits as when I search for "when I am done." Nevertheless, both are commonly used.

As has been pointed out, "it completes" is not a common expression. I would suppose you are meaning to say "it finishes," but I can't be sure. Let us know what "it" refers to and we could discuss this further.

[sh.hazeri]

"IT" is not refering to the email, it is something totally diffrent. Here is more explanation :

I will email ( all you guys ) again ( to inform you ) once it ( the automated process in a sepecific software application ) completes

[bhaisahab]

"IT" is not refering to the email, it is something totally diffrent. Here is more explanation :

I will email ( all you guys ) again ( to inform you ) once it ( the automated process in a sepecific software application ) completes

As kfredson said, you can use either one. They are interchangeable in that context.

[kfredson]

"IT" is not refering to the email, it is something totally diffrent. Here is more explanation :

I will email ( all you guys ) again ( to inform you ) once it ( the automated process in a sepecific software application ) completes

Thank you. That makes it clearer. I believe people say that a specific software application "completes its run," but I am not sure.

[joham]

Which one is more accurate and common ?

- I will email again once it completes
- I will email again when it completes

Can 'complete' be used as an intransitive verb? Thank you all.

[Barb_D]

Can 'complete' be used as an intransitive verb? Thank you all.

Not in normal use. It's possible that in IT use, it can be.

... once it's finished.
... once it's complete.
... once it completes the [process].