To reset a login password in OS X Mountain Lion or later, restart the Mac and hold down Command-R to boot into the Recovery HD partition. From the Utilities menu, choose Terminal to open it. In Terminal type:
and press Return.
In macOS Sierra and macOS High Sierra, an Reset Password assistant will launch. Choose the user account or admin account you want to reset the password for. Enter a new password, confirm the new password, set (if you like) a password hint and then click on "Next" to set the new password for the account in question. Choose to "Restart" the Mac and when the Mac boots up, use the newly reset password to login to the computer.
In OS X Mountain Lion, OS X Mavericks, OS X Yosemite and OS X El Capitan, a Reset Password window will appear that will list all the bootable volumes attached to your Mac. Select the volume that contains the account you want to reset and choose the user name that needs its password reset. Enter and verify a new passwords in the appropriate fields and, if you like, enter a password hint. Click Save and the new password is applied to the account.
Time Machine is the simplest way to keep regular backups of a Mac. On some rare occasions though, Time Machine may get stuck on the "Preparing backup…" stage for an inordinately long amount of time, causing a backup to never start. So lets fix this specific Time Machine issue.
The first thing you need to do is cease the currently failed backup attempt:
• Open System Preferences from the Apple menu and click "Time Machine"
• Click the (x) icon on the right side of the progress bar to stop the backup attempt
When the progress bar disappears and it no longer says "Preparing backup…" you're good to begin the troubleshooting process.
• Open the Time Machine drive in the Finder and navigate to the "Backups.backupd" folder
• Open the folder within Backups.backupd that is the name of the current Mac which is stuck on preparing
• Put this directory into "List View" and sort by ‘Date Modified', or just search the folder for a file with a ".inProgress" file extension
• Delete the "xxxx-xx-xx-xxxxxx.inProgress" file. The .inProgress file is always in the form of xxxx-xx-xx-xxxxxx.inProgress, where the first 8 digits are the year-month-day (date) and the next 6 or so digits are random numbers, followed by the inProgress file extension.
• Restart your Mac
• Once rebooted, let Spotlight run completely (you can either just wait it out or watch the mdworker, mrs, and related processes in Activity Monitor). This should cause macOS to re-index the attached Time Machine drive if it's needed, which may be getting in the way of Time Machine backing up properly thus causing the computer to get stuck on "Preparing backup..." for a very long time.
• Start a back up yourself. Pull down the Time Machine icon and choose "Back Up Now". You will still see a "Preparing backup…" message but it should be gone within a few minutes, depending on the size of the hard drive, the speed of the Mac, and the size of the backup to be made. At this point, your Time Machine backup will proceed as expected, so just let it run and you're good to go again.
If you have a MacBook, MacBook Air or MacBook Pro, you can check the battery cycle count to get an idea of overall battery health. Here’s how you can do that yourself, right from the macOS built in system management functions.
This works for all batteries in portable Mac models.
• Pull down the () Apple menu and choose "About This Mac".
• Click the "System Report…" button.
• Under Hardware, select "Power" and look for "Cycle Count" under the "Battery Information" portion.
The number shown is the cycle count of the current battery. A battery charge cycle is when the battery has been drained to 0% and then refilled to 100% of it's maximum capacity. Knowing the cycle count is helpful if you suspect your battery is having problems retaining a charge. Apple says new notebook batteries are designed to retain 80% of original capacity after 1000 cycles. If your battery is performing at less than expected and is still under warranty, it may be a good idea to schedule an appointment with an Apple Genius.
Those who use external Bluetooth devices with a Mac, whether it's a keyboard, mouse, headset, or anything else, are probably aware that connection strength between the device and the computer is going to directly impact how usable the device is.
If your Bluetooth device connections seem flakey, or if your wireless keyboard or mouse isn't as responsive as you think it should be with your Mac, there is a easy way to check Bluetooth signal strength in macOS. Simply Option (Alt) click the Bluetooth menu bar item, then move the mouse cursor over the Bluetooth item you want to check the signal strength for and look for "RSSI".
RSSI (Received Signal Strength Indicator) can be a bit weird to read, but essentially a higher number means a better connection, and a lower number means a worse connection. Note however that the numbers are negative, so that may read opposite to what you'd expect. For example, a connection of -45 is significantly stronger and better than a connection of -100, which is weaker and more likely to have issues. The rough guidelines below may help read the connection, though the precise signal you get is going to vary on other factors we’ll discuss below:
-40 to -55 is a very strong connection
-70 and above represents a good connection
-100 and below represents a bad connection
-110 and below is almost unusable
The two most likely reasons for a bad Bluetooth connection are low batteries and heavy interference from something in the environment. Batteries are easy to test, all you need to do is swap in a new set of batteries or charge the device in question and see if the RSSI increases and if the device becomes more stable. Environmental factors can be trickier to track down, but if you see a huge drop in the RSSI when you move a headset behind a fireplace for example, you can surmise that something in the wall is causing the interference and you should rearrange the equipment accordingly. It's also vaguely possible that the device itself has a defective antenna, though that’s fairly rare for most quality devices.
In general, applications in macOS are packaged into a ".app" bundle that appears to be a single file but is actually a self-contained folder. Unlike Windows, in which an application usually installs a folder that contains the executable and supporting files, most of what an macOS app needs to run is stored within the .app bundle. Deleting an application bundle will remove that application's binary and all the supporting files contained within. Many apps, however, also install additional files in the user's Library folder, such as application preferences and caches.
To manually remove an macOS app, make sure the app is closed and head to the user's Library folder (in OS X Lion and above, hold down the Option key while selecting the Go menu from the Finder's menu bar and select Library). Here, you'll want to check for references to the application in the Application Support, Caches, LaunchAgents, and Preferences folders. Remove any files or folders that you are certain belong to the application you're trying to uninstall. You may also want to check the main Library folder by navigating to the top level of your hard drive and opening the /Library folder, although most applications will confine their files to the user-specific Library. Due to sandboxing requirements imposed by Apple, apps obtained from the Mac App Store are even easier to remove. Simply delete two items: the application file itself from the Applications folder and the application-specific folder in ~/Library/Containers (user's Library folder).
Another way to remove macOS apps is to use third-party tools. Take note, however, that automated tools can sometimes miss certain files or folders, and users employing these tools should always perform a manual check to ensure that all remnants of the application have indeed been removed. Finally, some applications (such as Cocktail) have their own uninstaller. Wherever possible, use the application-specific uninstaller for these applications.
Regardless of which method you choose, remember that leaving behind the occasional abandoned preference file is not likely to cause harm or performance issues. In general, removing the app bundle from the Applications folder and a file or two from the user's Library folder is enough to remove the application from the drive and free up disk space.