You may have noticed that sometimes you can not power on and boot a MacBook Pro when it doesn’t have a battery installed. Let’s say you had to remove the battery of an older MacBook Pro because it was swelling, or the battery failed for some other reason, but when you go to power on the MacBook Pro, nothing happens. (To be clear, this article is aimed at older MacBook Pro model years, like a 2006, 2007, 2008, 2009, 2010, 2011, back when replacing a battery, hard disk, RAM, was all fairly easy to do by opening the bottom case).

In this situation, if a battery is removed or totally dead and you attempt to start the MacBook Pro, nothing happens – there is no sound, no system boot, no startup chime, nothing. It turns out that some model year MacBook Pro computers will not boot with a simple power button press after the battery has been physically removed or disconnected.

Of course if you happen to have a replacement battery then you can typically just replace the missing battery with a working battery and the MacBook Pro will boot, but that is not always an option. So let’s discuss how to boot an older MacBook Pro when there is no battery present at all.

How to Boot MacBook Pro with No Battery Installed

We are assuming the MacBook Pro has no battery installed in the computer, meaning there physically is no battery installed. Then, when attempting to boot the Mac or pressing the start button, nothing happens. In this case, you can force the MacBook Pro to boot by following these steps:

1. Unplug the MagSafe power cable
2. Hold down the Power button for 10 seconds and continue to hold it down
3. While still holding the Power button, connect the MagSafe power cable to the MacBook Pro and continue to hold the Power button for another 10 seconds
4. Release the Power button, then press the Power button as usual to power on the computer and boot the Mac

When the MacBook Pro does boot, the fans will be blasting at full speed for the entire time you are using the Mac (resetting SMC or PRAM does not stop the fans running, only replacing the battery will).

Also it appears that the MacBook Pro will reduce its own clock speed in this situation, thereby reducing performance.

The only way to stop the fans from running at full speed and to return the clock speed to regular performance is to install a new battery into the MacBook Pro.

As some experienced this scenario on an old MacBook Pro 2010 model after removing a swollen battery. Once the battery was removed you can press the power button but nothing happens. However, the above method of disconnecting and reconnecting MagSafe while holding the Power button was successful in starting up the Mac – with fans running at full speed and at reduced clock speed however. Nonetheless, Snow Leopard still runs well!

As you can see in the screenshot below, the “No Battery” indicator is visible, but the MacBook Pro is booted and working.

And indeed, this particular MacBook Pro has no physical battery installed as you can see the internals in this picture:

Powering Up a MacBook Pro After Replacing Battery, Logic Board, Hard Drive, RAM, etc too

Apparently the same aforementioned scenario of the MacBook / MacBook Pro not starting up can also unfold when replacing other internal components on these older model year MacBook Pro (2006, 2007, 2008, 2009, 2010, 2011, etc), including replaced logic boards, internal hard drives, RAM, battery, and perhaps other hardware components too.

With some other internal component replacements, sometimes simply plugging in the MagSafe adapter and holding the power button for 10 seconds is enough to cause the MacBook Pro to start.

Also, Check the Power Adapter Wattage

For what it’s worth, in some scenarios where the battery appears dead but is not actually (ie, the charge is long drained but the battery itself isn’t completely useless yet), then you may be able to successfully boot the MacBook Pro with a proper wattage MagSafe power adapter of 85W. These older model year MacBook Pro computers use 85W power adapters, whereas the MacBook and MacBook Air of the same generation used 60W power adapters. Sometimes simply plugging in the proper higher wattage power adapter will allow the MacBook Pro to boot.

This MagSafe power button pressing solution was found on iFixIt forums and it worked for me, so if you’re in a similar scenario with an older MacBook Pro then try it out yourself. If for some reason the above method does not work, the original forum poster does state the following possible workaround involving moving a RAM module to a different slot (if applicable):

“If that doesn’t work then try to remove one RAM memory [module] and switch places and [repeat] the method”

In my case this juggling of the RAM module was not necessary to boot the MacBook Pro (a 2010 model year) without a battery, but that additional tidbit may be valid to you.

This article is obviously aimed at older MacBook Pro hardware, but it may be relevant to other older MacBook models too, including similar model year (2006, 2007, 2008, 2009, 2010, 2011) MacBook and MacBook Air, and perhaps even some newer MacBook Pro models too. By the way, if you’re rocking an older Mac and want to speed it up, check out these tips.

Of course newer model year MacBook (Pro & Air too) hardware does not have user serviceable batteries and in some cases the battery is glued to the top case, so in those situations the ability to end up in a situation where the computer doesn’t have a battery is much less likely, and any troubleshooting scenario is going to be much more extreme requiring a more thorough hardware repair that is far beyond the scope of this particular article. In those situations, take the Mac to a certified Apple Repair Specialist or an Apple Store instead.

Long live the old Macs! Does this qualify for retro status yet? Probably not… give it a bit longer.