+++ This bug was initially created as a clone of Bug #1379245 +++ Some context: - Bug 848460 reduced this from 60 seconds to 50 and then 45 seconds - Bug 1015619 reduced it to 40 seconds - Bug 1298945 made it so that we only show the slow startup notification in old profiles where a reset is likely to help - Bug 1379245 reduced the threshold to 30 seconds - The first paint taking >20 seconds affects about 10% of users in 54, but with legacy add-on deprecation and recent efforts to improve startup time, hopefully this share will be smaller in 57? A more conservative step would be 25 seconds (currently amounts to about 8%).

10% seems high but I agree that number should drop with the changes you mention. What do nightly numbers look like right now and what is the startup time on the reference hardware?

(In reply to Dave Townsend [:mossop] from comment #2) > 10% seems high but I agree that number should drop with the changes you > mention. It's not necessarily a bad thing. The more users this can help, the better. We just shouldn't be surprised by how many users might see this. > What do nightly numbers look like right now For 9.26% of Nighty 57 users, the first paint happens after 30(!) seconds. Not sure what's going on there. The trend is positive though: https://telemetry.mozilla.org/new-pipeline/evo.html#!aggregates=median&cumulative=0&end_date=2017-08-10&keys=!__none__!__none__&max_channel_version=nightly%252F57&measure=SIMPLE_MEASURES_FIRSTPAINT&min_channel_version=nightly%252F54&processType=*&product=Firefox&sanitize=1&sort_keys=submissions&start_date=2017-08-02&trim=1&use_submission_date=0 > and what is the startup time on the reference hardware? I don't know, I could check next week at the office.

Comment on attachment 8896412 [details] Bug 1389590 - Reduce browser.slowStartup.timeThreshold to 20 seconds. https://reviewboard.mozilla.org/r/167654/#review173552 Let's do this but keep an eye on telemetry.

Pushed by dgottwald@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/d1025dcf203f Reduce browser.slowStartup.timeThreshold to 20 seconds. r=mossop

I have reproduced this bug with Nightly 57.0a1 (2017-08-11) on Windows 8.1 , 64 Bit ! This bug's fix is Verified with latest Beta 57.0b3 ! Build ID 20170925150345 User Agent Mozilla/5.0 (Windows NT 6.3; WOW64; rv:57.0) Gecko/20100101 Firefox/57.0

I have reproduced this bug with Nightly 57.0a1 (2017-08-11) (64-bit) on Ubuntu 16.04 LTS! This bug's fix is Verified with latest Beta! Build ID 20170925150345 User Agent Mozilla/5.0 (X11; Linux x86_64; rv:57.0) Gecko/20100101 Firefox/57.0 [bugday-20170927]

As par Comment 7 & Comment 8 , I am marking this bug as Verified Fixed !