[qayxc]

> Usually progress bars implicitly measure "time left", but the total isn't known in that case, so progress bars are inapproprate.

Are you sure about that? I'd argue that most progress bars explicitly measure tasks/work left and it's the user who wrongly correlates this with "time left" in many cases.

Note that the OP didn't complain about time, but about the percentage not going from 0% to 100% for example.

[news_to_me]

Yeah, you might be right about that. Still, that's not using a progress bar correctly if it's measuring multiple tasks — they should be measured individually, with spinners or a segmented progress bar.

[saagarjha]

Many progress bars are implicitly segmented; it's just that segments are determined by the programmer and never exposed to the user.