My iMac won't start normally it will start on safe boot unless I start in verbus mode single user mode or reset the pram but if I start this way it won't sleep

Question

help mi imac won't start normally

Answer 1

Hello!
Can you tell us what happens?
I’ve offered the steps below to similar posts in the past and they helped out getting to the solution (or at least find the cause). I suggest them to you too in this case. It will take you about 30 minutes or less to do these, depending on how bad the problem on your Mac is.
The goal here is to boot your Mac to the so-called Recovery partition where you’ll have a chance to repair the disk and the disk permissions using the Disk Utility and Password Utility. This might solve your issue and even if it doesn’t- it’s still a decent maintenance step to perform. These steps won’t erase your data or reinstall your Mac in any way if you follow instructions carefully.
Here’s how:
1/ Make sure your computer is completely shut down.
2/ You’ll have to be quick next: Press the Mac’s power button. As soon as you either hear the loud chime, or see the display light up - usually after a second or 2 - on your keyboard press [cmd] + [r] Keep these keys on your keyboard pressed until you either see an Apple Logo with a loading bar or a spinning gear.
After a few minutes, you’ll be presented with a Utilities screen. This is the Recovery partition. If this step is already giving you problems, try using a USB-keyboard. It doesn’t have to be an Apple-keyboard. If you have a Windows-tailored keyboard laying around, use the “Windows-flag” key in stead of the [cmd]-key and it should also work.
3/ Choose Disk Utility and click [continue]
Disk Utility will display your computer’s harddrive in the left column. The default name for it is “Macintosh HD” and is usually the second one from the top. Click on it and click on the [verify disk] button. This will check your “Macintosh HD” harddrive partition for errors. If found, click [repair disk]  unless you have a Fusion drive in your Mac and it says [fix] instead of [repair disk] please tell us before you continue! For a screenshot of what I mean, check this article from Apple: http://support.apple.com/en-us/HT202574
4/ Once done with the verifying or repairing of your “Macintosh HD” click [repair disk permissions]
This will check your partition for permissions errors. A common myth about this feature is that it will fix all permissions issues on your Mac, which is not true, but it will fix most systemwide issues. Also, here is a list of error messages that you can safely ignore if they pop up:
http://support.apple.com/en-us/HT203172
5/ Lastly we shall do a permissions/Access Control List repair on specifically your user’s home folder with a somewhat hidden tool in the Recovery partition. Close Disk Utility and find the menu called “utilities” in the top left corner of your computer’s display. It’s in between the menus “edit” and “window” Don’t be confused with the menu called “os x utilities” 
Choose Terminal. A somewhat old-fashioned looking window will pop up, waiting for a text command from you. This is the Terminal.
After the # type: resetpassword and press return. Note that there is no space between ‘reset’ and ‘password’ 
What you’ll see next is an rectangular window that gives you the option to reset passwords. We are not going to that, however. Instead, click on “Macintosh HD” at the top. In the pull-down menu below that, choose your user's accountname. Skip all the rest and at the very bottom click the [reset]-button.
A spinning gear will appear and may stay on for a second or several minutes. It’s hard to predict exactly how long.
If you have multiple users on your Mac, I advise you to repeat this step for all your users.
We’re ready to reboot your Mac now. Click on the Apple Menu and choose “startup disk” Choose to boot from “Macintosh HD” Please let us know if this solved your issue, or if the steps above did not work, or could not be performed for some reason.