Practically all modern operating systems are recoverable systems. That is, the “OS” can be returned to a certain state that preceded some specific moment (crashes, errors, etc.). As an example, consider the recovery (rollback) processes used in Windows.
Recoverable Windows systems: Processes used
First, a little theory. As it is already clear, recoverable systems are named so because they have in their arsenal tools for returning to their original state. The principle of their work is quite simple. The system reserves a certain place on the hard drive, where special backups are stored in the form of an image of the system with files critical for its operation.
When restoring Windows, user files and documents cannot be changed, no matter what period of time they were created. Only installed programs that were installed after the rollback point was created are affected. But this is the simplest explanation, because in fact everything is muchmore difficult. But an ordinary user does not need to climb into the wilds of system processes and services, so let's focus on practical actions.
How to restore the system with the simplest method?
There are several ways to restore the system after failures or errors, when it does not work correctly due to their appearance. The simplest method is considered to be the use of a special service located in the corresponding section of the Control Panel.
Here you simply choose to start the rollback process, after which the system shows a list of all states (so-called checkpoints) to which it can be restored. In the event that an unexpected failure occurs or the user wants to rollback to a different time indicator, the display of all points should be used, and not just those that were automatically created by the system. After activating the process, a reboot will follow, and the system will be brought to the form that corresponded to the selected point.
Sometimes you can perform similar actions when changing the OS to a newer modification. In particular, this applies to upgrading from Windows 7 or 8 to the tenth version. How to restore the system to the 8th version instead of the 10th? For this, the standard method is not suitable. You will have to use a rollback to the previous OS. In the recovery partition itself, there is such a line. But you need to remember that a rollback after installing Windows 10 to the OS that was previously used on the computer can only be done within30 days. You can restore system 8.1 or 7, on top of which the tenth modification was installed, in a similar way.
Actions at system boot
However, quite often you can find situations where there is no access to the standard rollback tool, if only because the system simply cannot boot in normal mode.
Recoverable Windows systems have at their disposal another unique tool, the use of which is to call up a special menu at OS startup before the GUI boot window appears. In all versions of Windows except the tenth, the F8 key is used (in Windows 10 it can also be configured). When you click on it at the very beginning of the start, the line for loading the last working configuration automatically saved on the computer is selected from the menu. This is somewhat similar to the standard rollback process, only the time point is chosen by the system itself, and not by the user.
Rollback after failures in Safe Mode
But what if the rollback is impossible even when using this method? There are several options here, one of which is to try to get to the recovery tool yourself.
To do this, as in the previous case, the F8 key is used, but in the start menu, the Safe Mode line, called safe, is selected. At the same time, the minimum elements necessary for the normal operation of the OS are loaded. If the system has booted,just repeat the steps described for the standard method.
Restoring from backup
Many users, unfortunately, completely underestimate the creation of manual backups in the form of images of a he althy OS and their own files when using Windows tools or special programs.
But with their help, making a rollback is much easier than using tools that require additional knowledge. In addition, a backup copy can be saved on a hard drive, and written to an optical or USB drive so that it can be booted from it initially.
How to restore the system through BIOS (Windows)?
Since we're talking about removable media, we can't help but touch on the related BIOS settings for the primary input/output system.
The main rule for all situations is to set the boot priority for a removable device. But if there are no problems for optical discs (the CD / DVD drive is automatically recognized in the BIOS), then when you try to install the flash drive as the first component, you need to insert it into the USB port before turning on the computer or laptop. Otherwise, the device may not be detected. If everything is done correctly, its name or description will be shown in the download list.
Using bootable media
Now a few words about what should be present on the boot device. First of all, it must contain boot sectors, withoutwhich start will be impossible. As for the rest of the software, it can be divided into two broad categories:
- installation system distributions;
- boot utilities like LiveCD, not related to any one modification of Windows.
But in both cases, they have built-in troubleshooting and rollback tools. However, experts recommend using the command line. In most cases, in case of especially critical damage to the system, the only way to restore the operating system is.
For example, one of the most versatile commands that will come in handy for all occasions is sfc /scannow (it checks the integrity of system components and, if necessary, also restores them).
If the bootloader and its corresponding boot record are damaged, first use the command to check the system partition (chkdsk c: /f /r), and then restore or completely overwrite the boot (Bootrec.exe /FixMbr, Bootrec.exe /FixBoot, Bootrec.exe /RebuildBcd). These are the tools that help when all else fails.
Specific rollback methods on some laptop models
But on some laptop models, all these tools are unnecessary. They have special menus that can be accessed using the buttons on the keyboard panel or on the case (for example, in Sony VAIO this is the ASSIST button).
In these menus, you can restore the system after reinstallation evenwith a modification change or after the occurrence of critical errors and failures. In addition, you can return to the factory settings that were originally set (hard reset). After that, the user will receive a "clean" system, however, all data will be destroyed.
Problems of hard drives with the RAW file system
Finally, one more problem, after the appearance of which you have to think about how to restore the system. The RAW format of hard drives, as well as removable drives, is a specific file system that, although recognized by Windows, is nevertheless impossible to extract information from it.
In the simplest case, if this is not a system partition, you can convert the RAW format to NTFS or FAT32 in the disk management options. In the case of a system disk, you will have to use boot from removable media and use the check command with the partition letter.
If this does not give the desired effect, you can use the special boot utility Active Partition Recovery Boot Disk, which is specifically designed to fix problems with the system partition (including converting RAW format to any other). If this does not help, the partition will have to be completely formatted and the operating system reinstalled.
Conclusion
Finally, it remains to add that the Windows rollback tool used in each specific case should be chosen solely taking into account the current situation. With minor damage, both Safe Mode and loading the last working configuration work. If failures and errors occur constantly, and the system does not boot at all, you cannot do without removable media and the command console. In many cases, the only way to bring the system to life is with its help.
