iMac turned itself on after power was cut
I left my computer sleeping but turned off the power by accident. Hours after the power was turned back on the computer booted itself up. It is plugged into a UPS. I don't understand how this could happen.
imac
edited Dec 31 '18 at 13:19
wizzwizz4
1086
asked Dec 31 '18 at 7:33
DebraDebra
311
add a comment |
I left my computer sleeping but turned off the power by accident. Hours after the power was turned back on the computer booted itself up. It is plugged into a UPS. I don't understand how this could happen.
imac
edited Dec 31 '18 at 13:19
wizzwizz4
1086
asked Dec 31 '18 at 7:33
DebraDebra
311
Is the "start on power" selected in the system preferences? if so it will start on getting power...
– Solar Mike
Dec 31 '18 at 8:54
December 30, 2018. Skynet becomes self aware.
– Terminator
Jan 1 at 1:07
add a comment |
I left my computer sleeping but turned off the power by accident. Hours after the power was turned back on the computer booted itself up. It is plugged into a UPS. I don't understand how this could happen.
imac
edited Dec 31 '18 at 13:19
wizzwizz4
1086
asked Dec 31 '18 at 7:33
DebraDebra
311
I left my computer sleeping but turned off the power by accident. Hours after the power was turned back on the computer booted itself up. It is plugged into a UPS. I don't understand how this could happen.
imac
imac
edited Dec 31 '18 at 13:19
wizzwizz4
1086
asked Dec 31 '18 at 7:33
DebraDebra
311
edited Dec 31 '18 at 13:19
wizzwizz4
1086
asked Dec 31 '18 at 7:33
DebraDebra
311
edited Dec 31 '18 at 13:19
wizzwizz4
1086
edited Dec 31 '18 at 13:19
wizzwizz4
1086
edited Dec 31 '18 at 13:19
wizzwizz4
1086
1086
asked Dec 31 '18 at 7:33
DebraDebra
311
asked Dec 31 '18 at 7:33
DebraDebra
311
asked Dec 31 '18 at 7:33
DebraDebra
311
311
Is the "start on power" selected in the system preferences? if so it will start on getting power...
– Solar Mike
Dec 31 '18 at 8:54
December 30, 2018. Skynet becomes self aware.
– Terminator
Jan 1 at 1:07
add a comment |
Is the "start on power" selected in the system preferences? if so it will start on getting power...
– Solar Mike
Dec 31 '18 at 8:54
December 30, 2018. Skynet becomes self aware.
– Terminator
Jan 1 at 1:07
Is the "start on power" selected in the system preferences? if so it will start on getting power...
– Solar Mike
Dec 31 '18 at 8:54
Is the "start on power" selected in the system preferences? if so it will start on getting power...
– Solar Mike
Dec 31 '18 at 8:54
December 30, 2018. Skynet becomes self aware.
– Terminator
Jan 1 at 1:07
December 30, 2018. Skynet becomes self aware.
– Terminator
Jan 1 at 1:07
add a comment |
1 Answer
1
active
oldest
votes
On the iMac, there's a setting under System Preferences > Energy Saver called Start up automatically after a power failure, which I'm guessing will be selected on your system, and hence would explain your computer's spontaneous rebooting.
If you don't wish this to happen in the event of a power failure, or the next time you turn off the power by accident, then uncheck that particular option.
Note: Screenshot taken on macOS 10.12.6 (Sierra)
As Tetsujin very helpfully points out in the comments below, there is also a button in the bottom right of the Energy Saver preferences pane labelled "Schedule...", which allows the user to regulate when the computer starts up, wakes up, or goes to sleep. It would be wise to double check your settings there too.
answered Dec 31 '18 at 8:56
CJKCJK
2,803114
1
There's also the Schedule, bottom right, which could potentially explain why it switched on hours later.
– Tetsujin
Dec 31 '18 at 9:09
1
Thanks @Tetsujin. I misread the OP as saying "Hours_later_, the power was turned back on...". I'll add your comment to the answer, as it's a very pertinent detail.
– CJK
Dec 31 '18 at 9:29
1
There is also the remote possibility that the UPS spent the first few hours recharging before pushing power to the Mac, but I don't know enough about UPS to know if that's a valid suggestion.
– Tetsujin
Dec 31 '18 at 9:33
@Tetsujin yes, for a ups that can happen - depends how it can be configured... sure the answer will get updated to include that...
– Solar Mike
Dec 31 '18 at 10:56
add a comment |
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1 Answer
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On the iMac, there's a setting under System Preferences > Energy Saver called Start up automatically after a power failure, which I'm guessing will be selected on your system, and hence would explain your computer's spontaneous rebooting.
If you don't wish this to happen in the event of a power failure, or the next time you turn off the power by accident, then uncheck that particular option.
Note: Screenshot taken on macOS 10.12.6 (Sierra)
As Tetsujin very helpfully points out in the comments below, there is also a button in the bottom right of the Energy Saver preferences pane labelled "Schedule...", which allows the user to regulate when the computer starts up, wakes up, or goes to sleep. It would be wise to double check your settings there too.
answered Dec 31 '18 at 8:56
CJKCJK
2,803114
1
There's also the Schedule, bottom right, which could potentially explain why it switched on hours later.
– Tetsujin
Dec 31 '18 at 9:09
1
Thanks @Tetsujin. I misread the OP as saying "Hours_later_, the power was turned back on...". I'll add your comment to the answer, as it's a very pertinent detail.
– CJK
Dec 31 '18 at 9:29
1
There is also the remote possibility that the UPS spent the first few hours recharging before pushing power to the Mac, but I don't know enough about UPS to know if that's a valid suggestion.
– Tetsujin
Dec 31 '18 at 9:33
@Tetsujin yes, for a ups that can happen - depends how it can be configured... sure the answer will get updated to include that...
– Solar Mike
Dec 31 '18 at 10:56
add a comment |
On the iMac, there's a setting under System Preferences > Energy Saver called Start up automatically after a power failure, which I'm guessing will be selected on your system, and hence would explain your computer's spontaneous rebooting.
If you don't wish this to happen in the event of a power failure, or the next time you turn off the power by accident, then uncheck that particular option.
Note: Screenshot taken on macOS 10.12.6 (Sierra)
As Tetsujin very helpfully points out in the comments below, there is also a button in the bottom right of the Energy Saver preferences pane labelled "Schedule...", which allows the user to regulate when the computer starts up, wakes up, or goes to sleep. It would be wise to double check your settings there too.
answered Dec 31 '18 at 8:56
CJKCJK
2,803114
1
There's also the Schedule, bottom right, which could potentially explain why it switched on hours later.
– Tetsujin
Dec 31 '18 at 9:09
1
Thanks @Tetsujin. I misread the OP as saying "Hours_later_, the power was turned back on...". I'll add your comment to the answer, as it's a very pertinent detail.
– CJK
Dec 31 '18 at 9:29
1
There is also the remote possibility that the UPS spent the first few hours recharging before pushing power to the Mac, but I don't know enough about UPS to know if that's a valid suggestion.
– Tetsujin
Dec 31 '18 at 9:33
@Tetsujin yes, for a ups that can happen - depends how it can be configured... sure the answer will get updated to include that...
– Solar Mike
Dec 31 '18 at 10:56
add a comment |
On the iMac, there's a setting under System Preferences > Energy Saver called Start up automatically after a power failure, which I'm guessing will be selected on your system, and hence would explain your computer's spontaneous rebooting.
If you don't wish this to happen in the event of a power failure, or the next time you turn off the power by accident, then uncheck that particular option.
Note: Screenshot taken on macOS 10.12.6 (Sierra)
As Tetsujin very helpfully points out in the comments below, there is also a button in the bottom right of the Energy Saver preferences pane labelled "Schedule...", which allows the user to regulate when the computer starts up, wakes up, or goes to sleep. It would be wise to double check your settings there too.
answered Dec 31 '18 at 8:56
CJKCJK
2,803114
On the iMac, there's a setting under System Preferences > Energy Saver called Start up automatically after a power failure, which I'm guessing will be selected on your system, and hence would explain your computer's spontaneous rebooting.
If you don't wish this to happen in the event of a power failure, or the next time you turn off the power by accident, then uncheck that particular option.
Note: Screenshot taken on macOS 10.12.6 (Sierra)
As Tetsujin very helpfully points out in the comments below, there is also a button in the bottom right of the Energy Saver preferences pane labelled "Schedule...", which allows the user to regulate when the computer starts up, wakes up, or goes to sleep. It would be wise to double check your settings there too.
answered Dec 31 '18 at 8:56
CJKCJK
2,803114
edited Dec 31 '18 at 9:36
answered Dec 31 '18 at 8:56
CJKCJK
2,803114
answered Dec 31 '18 at 8:56
CJKCJK
2,803114
answered Dec 31 '18 at 8:56
CJKCJK
2,803114
2,803114
1
There's also the Schedule, bottom right, which could potentially explain why it switched on hours later.
– Tetsujin
Dec 31 '18 at 9:09
1
Thanks @Tetsujin. I misread the OP as saying "Hours_later_, the power was turned back on...". I'll add your comment to the answer, as it's a very pertinent detail.
– CJK
Dec 31 '18 at 9:29
1
There is also the remote possibility that the UPS spent the first few hours recharging before pushing power to the Mac, but I don't know enough about UPS to know if that's a valid suggestion.
– Tetsujin
Dec 31 '18 at 9:33
@Tetsujin yes, for a ups that can happen - depends how it can be configured... sure the answer will get updated to include that...
– Solar Mike
Dec 31 '18 at 10:56
add a comment |
1
There's also the Schedule, bottom right, which could potentially explain why it switched on hours later.
– Tetsujin
Dec 31 '18 at 9:09
1
Thanks @Tetsujin. I misread the OP as saying "Hours_later_, the power was turned back on...". I'll add your comment to the answer, as it's a very pertinent detail.
– CJK
Dec 31 '18 at 9:29
1
There is also the remote possibility that the UPS spent the first few hours recharging before pushing power to the Mac, but I don't know enough about UPS to know if that's a valid suggestion.
– Tetsujin
Dec 31 '18 at 9:33
@Tetsujin yes, for a ups that can happen - depends how it can be configured... sure the answer will get updated to include that...
– Solar Mike
Dec 31 '18 at 10:56
1
1
There's also the Schedule, bottom right, which could potentially explain why it switched on hours later.
– Tetsujin
Dec 31 '18 at 9:09
There's also the Schedule, bottom right, which could potentially explain why it switched on hours later.
– Tetsujin
Dec 31 '18 at 9:09
1
1
Thanks @Tetsujin. I misread the OP as saying "Hours_later_, the power was turned back on...". I'll add your comment to the answer, as it's a very pertinent detail.
– CJK
Dec 31 '18 at 9:29
Thanks @Tetsujin. I misread the OP as saying "Hours_later_, the power was turned back on...". I'll add your comment to the answer, as it's a very pertinent detail.
– CJK
Dec 31 '18 at 9:29
1
1
There is also the remote possibility that the UPS spent the first few hours recharging before pushing power to the Mac, but I don't know enough about UPS to know if that's a valid suggestion.
– Tetsujin
Dec 31 '18 at 9:33
There is also the remote possibility that the UPS spent the first few hours recharging before pushing power to the Mac, but I don't know enough about UPS to know if that's a valid suggestion.
– Tetsujin
Dec 31 '18 at 9:33
@Tetsujin yes, for a ups that can happen - depends how it can be configured... sure the answer will get updated to include that...
– Solar Mike
Dec 31 '18 at 10:56
@Tetsujin yes, for a ups that can happen - depends how it can be configured... sure the answer will get updated to include that...
– Solar Mike
Dec 31 '18 at 10:56
add a comment |
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Is the "start on power" selected in the system preferences? if so it will start on getting power...
– Solar Mike
Dec 31 '18 at 8:54
December 30, 2018. Skynet becomes self aware.
– Terminator
Jan 1 at 1:07