Speech Downloader pop up
Omer begins, "Using Safari..." Which is odd, since for me the popup relates to my (no-microphone and no-Siri) System Preferences, Date & Time, Announce the time: On the hour Customize Voice... My custom voice download is Ava, American (there used to be enhanced version, requiring a further download, but the enhancement is now integrated into standard download with El Capitan+).
I do not use Siri, but I do use hourly time announcements. If I allow CleanMyMac to Force Quit All, the problem goes away for 24x7=168 hours. During that wait, Ava begins announcing time hourly again, usually a day later. If go to downloads, perhaps because I have no microphone and no Siri, there is nothing to download. AppleCare Senior Advisors can trigger a download, but the download does not appear to do anything. A week later the warning re-appears. Safari?
It is true that Safari is perching on the Speech Downloader warning popup. I have two displays, and CleanMyMac is installed: I get two Speech Downloader popups. First the system popup. Then the CleanMyMac popup. Whatever display I drag Safari to ('Air Display' off and 'Show mirroring options' on, each display in separate space), that Safari-focused display automatically moves the CleanMyMac popup from display where Safari was, to the display where Safari is moved to!
But, the initial system Speech Downloader stays on newer 4K Docked display (actually rated early 5K, BL3200 34" 2560x1440), horizontal center. But same distance from top of 4K display that would make dead center vertically on the older 2K un-Docked display (Acer SL243 24" 1920x1080). Anyway, System popup stays on 4K, while Safari CleanMyMac popup drags to whatever display Safari window is using.
system popup
Safari/CleanMyMac popup
Note! This is my second collision using Apple Speech Downloader. I have had same problem on 2015 and 2016 Mac Pro new machines, using the same 4K-2K display combination on both new models.
My Mac Pro desktop installs 4K as the Docked display because Apple prefers using a better display, but Lazy Dock in OS X prefers 2K. Constant tug of war for Dock between 2K and 4K. 2K uses smaller, cheaper real estate, which may relate to Safari dragging CleanMyMac from 4K to 2K (back and forth). First, if we install pre OS X, then cannot even use 2.n billion color 4K (5K) display. Second, Apple engineers cannot work out lazy Dock slipping back from OS X 4K install preference to lazy real estate saavy 2K. I have been told by Apple, use 2K power switch to correct dock slip. Also resets Speech Downloader CleanMyMac popup to 4K, except one condition cited below.
Anyway, 4K system popup always comes first, followed by CleanMyMac popup a few seconds later, both on 4K. Sometimes this Speech Downloader error will freak Apple system just after the CleanMyMac, initiating the Lazy Dock: that is, CleanMyMac popup appears to cause the Dock slip! Leaving the system popup alone in 4K. When power-switch correction advised by AppleCare Senior Advisor for previous 2015 Mac Pro, then the CleanMyMac popup always does not reappear on the reset 4K! Occassionally, the Speech Downloader popup also disappears, a few seconds after the power-switch reset.
Safari and Siri getting hooked into Apple's 4K-2K war-of-the-display-worlds, a year after Omer brings up this issue, is also telling. I wish that I could offer more environmental continuity! Same 4K-2K displays, but my Feb 2015 Mac Pro with same displays had same 4K-2K war, with same popups. Apple engineers could not resolve that issue 2015, I was told to live with it. Now it looks like the very same issue on my new Oct 2016 Mac Pro. If complicated by by extending into the new Siri app, perhaps an expanding issue, which is not good.
It was an older 2015 Mac Pro purchase, where my previous 'slipping Dock' case was started and put on hold. Because new Mac Pro has entirely different case history, for AppleCare, I was told that we may have to start any existing case all over again, for new machine. Lazy Dock and Speech Downloader complication cannot necessarily be assumed to be related between 2015 and 2016 Mac Pros. However, 2016-2017 Apple Speech Downloader problem migration (and/with piggy-back Lazy Dock). Also not that after the time it took to compose this post using TextEdit on 4K with Safari and ClenMyMac popup on 2K, Safari stayed on 2K but the CleanMyMac popup drifted back to 4K.
I don't want to do a repeat thread, so I will leave this here for the AppleCare Team, thank you.