I am unable to upload a file in my computer, what i want to upload.
I am unable to upload a file in my computer that i want to upload.
What is the difference between these sentences written above?
I am unable to upload a file in my computer, what i want to upload.
I am unable to upload a file in my computer that i want to upload.
What is the difference between these sentences written above?
I am unable to upload a file in my computer that I want to upload.
That one is OK but the other one is not. This one would also work with which instead of that as AndrewTobilko pointed out in a comment.
However it would be clearer to say
I am unable to upload a file from my computer
using from rather than in and deleting the last part since it does not really add any extra information.