Many inquisitive users, having one operating system on board their desktop computer or laptop, often experiment by installing a second one, for example, to compare it with the existing one or see how better or worse it will work. Usually, OS of the same type (for example, Windows) cannot be installed in one system partition, therefore, even during the installation process, the second OS is placed on a logical drive. When the time comes, and one of the existing systems (old or new) becomes unnecessary, many begin to wonder how to remove unnecessary operating systems from a computer without damaging the one that needs to be left to work. Simply deleting files and directories in one of the partitions, alas, does not lead to anything good, and often can even provoke situationswhen the required system stops booting at all. The following is a brief instruction, the observance of which will allow not only to get rid of the unnecessary OS completely and completely, but also to correct possible errors and failures.
How to uninstall an operating system from a computer: an introduction
So, for starters, let's dwell on some important points, the knowledge of which will further determine the correctness of all actions performed. When trying to remove any of the known operating systems (we consider Windows as an example), it should be clearly understood that it not only saves its own files and folders on a hard disk or logical partition, but also creates its own boot components used for a correct start, which usually hidden from the user's eyes. In the same way, special partitions are reserved for storing backups in case of unexpected failures. They are also invisible to the user.
Thus, if you have an urgent problem related to how to completely remove the operating system from your computer, you will have to tinker with all installed components and with all available partitions.
You can also offer several removal options to choose from. How comfortable they are, everyone decides for himself.
Remove OS when installing new version
As the very first and easiest method of removing unnecessary OS, we can offer a method familiar to everyone. It consists in simply installing another modification (updated or outdated) on top of the existing system,using the installation distribution from which the bootable media is created.
Speaking about how to remove 1 operating system from a computer, you can be advised to simply follow the instructions of the installer, and at one of the stages, when you are prompted to select a partition for installation, specify the one in which the unnecessary OS is located and install it exactly there, as if wiping the old one.
If this results in errors, you will first need to delete all existing partitions, including the one reserved by the system, and after the unallocated area appears, format it. If necessary, at the same stage, you can create additional virtual partitions.
Checking Windows system directory
Now let's move on to the main topic and see how to remove an unnecessary operating system from a computer, if there are two or more of them. First of all, you need to boot into the OS that you intend to leave for work.
After that, in the "Run" console (Win + R), you should register the combination % windir%, after which the root system directories will open in the "Explorer". The one that corresponds to the currently running system cannot be deleted! If the main OS is located on the C drive, the path to it will be shown as c:\Windows.
Pre-disable OS selection at PC startup
Now you need to disable the use of the bootloader for the system you want to get rid of.
To do this, enter the system configuration by entering the msconfig command, go to the boot tab, select the OS that you want to deactivate and click the delete button.
Note: the main OS you are currently running will be shown first in the list of available systems to start. It cannot be deleted!
Activation of the system partition
You are already halfway through the process of deciding how to remove an operating system from your computer that you no longer need. Since for each of the installed systems, the corresponding partition must be active at boot, you need to make the appropriate adjustments using the disk management tool (diskmgmt.msc) for this.
Here, when viewing the disk map, make sure that the partition being deleted is not active.
Use RMB on the partition with the system you want to leave, and select the option to activate it ("Make partition active"). Such actions are usually used when the second OS is installed in a logical partition, and the OS is removed from the main system partition on drive C.
Removing a partition with an unnecessary OS
Finally, the deactivation of all unnecessary OS components is done.
Now you just have to select the partition with the old system in the disk map, and then through the RMB select the item to delete it, agreeing with everyonewarnings to be issued. Upon completion of all operations, perform a complete restart of the computer. In theory, the system selection window for booting will not appear, and the remaining OS will boot normally.
Note: if there were more than two installed systems, you will need to delete all partitions in which they were originally installed.
Removing the old OS left after the upgrade
Now let's see how to remove an operating system from a computer that is recognized as the old (or second) after the upgrade. This can best be explained using the example of Windows 10, for which all kinds of updates are constantly installed, and the components of the previous version are stored in a special Windows.old directory. In this modification, you can use the standard rollback to the previous version, and the tools to perform the necessary operations can be found in the update and security section through the options menu.
But you need to delete her files and folders.
To do this, you can simply open the properties of the system disk through the RMB menu, click the cleanup button, and then additionally use the deletion of system files.
By and large, you can get rid of the specified folder manually.
Just before that, you will need to change the owner for it, which can be done in the directory properties, taking into account all subdirectories, and then set the full set of rights for yourself, including editing and deleting. But for security reasons, it is better to use the first method.
How to remove the 2nd operating system from the computer in the main running OS?
In principle, if you initially booted into the operating system that is supposed to be used to work as the main one, after disabling the choice of the preferred OS at startup and activating the remaining boot partition, as described above, you can do even easier. How to remove an operating system from a computer that is no longer needed for work, I think, many have already figured it out.
To do this, in a running OS, you just need to format the partition with the old OS using the most common "Explorer", but it is better to give preference to full formatting, rather than a quick cleaning of the table of contents. This method is good because at the end of the procedure you do not have to create a new partition again, using the "Simple Volume Wizard" for this, followed by size selection, letter assignment and formatting.
What if the remaining OS won't boot?
Lastly, let's assume that the remaining OS won't start for some reason (even with secure boot). You can fix such problems by starting from bootable media, in which, after selecting the language and region, system restore is selected, and then the startup restore item is used.
If this method does not work, use the command line call followed byBootrec.exe toolkit, when additional attributes shown in the image above are added after the main command to restore or overwrite the bootloader.
Note: absolutely all the actions described above in a running OS must be performed EXCLUSIVELY with administrator rights when logging into the corresponding account, if there are several of them, or confirm the performance of some actions on behalf of the super administrator if the built-in account is not disabled.