Almost all modern operating systems are recoverable systems. That is, the "OS" can be returned to a state that preceded any particular moment (failures, errors, etc.). As an example, consider the recovery (rollback) processes used in Windows.
Windows Recovery Systems: Processes Used
First, a little theory. As already understood, the systems being restored are therefore named because they have in their arsenal the tools to return to their original state. The principle of their work is quite simple. The system reserves a certain place on the hard disk, where special backup copies are saved in the form of an image of the system with files critical for its operation.
When restoring Windows, user files and documents are not subject to change, no matter in what period of time they were created. Only the installed programs that were installed after creating the rollback point are affected. But this is the simplest explanation, because in fact, everything is much more complicated. But the ordinary user does not need to climb into the jungle of system processes and services, so we will focus on practical actions.
How to restore the system in the simplest way?
There are several ways to restore a system after failures or errors, when it does not work correctly as a result of their appearance. The easiest method is the use of a special service located in the corresponding section of the “Control Panel”.
It simply selects the start of the rollback process, after which the system displays a list of all states (the so-called control points) to which it can be restored. In the event of an unexpected failure or the user wants to roll back to another time indicator, you should use the display of all points, and not just those that were automatically created by the system. After the process is activated, 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 upgrades from Windows 7 or 8 to the tenth version. How to restore the system to version 8 instead of version 10? For this, the standard method is not suitable. You have to use rollback to the previous OS. There is such a line in the recovery section itself. But you need to remember that rollback after installing Windows 10 to the OS that was previously used on the computer can only be completed within 30 days. You can restore the system 8.1 or 7, on top of which the tenth modification was installed, in the same way.
System Boot Actions
However, quite often you can meet situations when there is no access to the standard rollback tool, if only because the system simply cannot boot in normal mode.
Restored Windows systems have at their disposal yet another unique tool, the use of which is to call a special menu when the OS starts, even before the boot window with a graphical interface 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 boot line of the last working configuration automatically saved on the computer is selected from the menu. This is somewhat reminiscent of 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, using this method, rollback is impossible? There are several options for action, 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 the Safe Mode mode line, called safe, is selected in the start menu. At the same time, a minimum of elements necessary for the normal operation of the OS is loaded. If the system has booted, simply repeat the steps described for the standard method.
Restore from backup
Many users, unfortunately, completely underestimate the creation of backups in the form of images of a functioning OS and their own files manually 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, the backup can be saved on the hard drive, and burn it to an optical or USB-drive so that it can be booted from the beginning.
How to restore the system via BIOS (Windows)?
Since we are talking about removable media, you can not touch on the related parameter settings of the primary BIOS I / O system.
The main rule for all situations is to set the boot priority for the removable device. But if there are no problems for optical disks (a CD / DVD drive is automatically recognized in the BIOS), then when you try to install the first component of a flash drive, 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 should contain boot sectors, without which the start will be impossible. As for the rest of the software, it can be divided into two large categories:
- installation distributions of systems;
- boot utilities like LiveCD, which are not related to any one modification of Windows.
But in both cases, they have built-in troubleshooting tools and rollback tools. However, experts recommend using the command line. In most cases, with especially critical system damage, the OS can only be restored to functionality.
For example, one of the most universal commands that is useful for all occasions is sfc / scannow (it checks the integrity of system components, and if necessary also restores them).
In case of damage to the bootloader and the corresponding boot record, the system partition check command is first used (chkdsk c: / f / r), and then recovery or full rewriting of the boot (Bootrec.exe / FixMbr, Bootrec.exe / FixBoot, Bootrec.exe / RebuildBcd ) It is these tools that help when all else fails.
Specific rollback methods on some laptop models
But on some laptop models, all of 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 such menus, you can restore the system after reinstallation even with a modification or after the appearance of critical errors and failures. In addition, you can return to the factory settings that were set initially (full reset). After that, the user will receive a “clean” system, however, all data will be destroyed.
Hard Drive Issues with RAW File System
Finally, another 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 Windows recognizes, although it is not possible 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 settings. In the case of a system disk, you will have to use the boot from removable media and use the verification command with the letter of the partition.
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 eliminate problems that arise with the system partition (including converting the RAW format to any other). If this does not help, the section will have to be fully formatted and the operating system reinstalled.
Conclusion
In conclusion, it remains to add that the Windows rollback tool used in each particular case should be selected solely taking into account the current situation. With minor damage, both Safe Mode and loading of the last working configuration work. If crashes and errors occur all the time, and the system does not boot at all, you cannot do without removable media and a command console. In many cases, you can bring the system to life only with its help.