Thread: How to safely edit the registry

Back up, back up, back up

Before venturing any further with this Masterclass, it is important to point out that editing the Registry is potentially very dangerous. Accidentally change the wrong setting and Windows, and thus your PC, may become inoperable.

Be warned: we will not accept the blame for any problems you encounter as a result of following this Masterclass. Be sure to have a backup in place so things can be brought back to normal should the worst happen. Create a System Restore point and back up valuable data before proceeding with any editing. If you do not know how to back up your PC then this really isn't the kind of feature you should be following. It is also worth mentioning that when editing the Registry, there is no 'undo' feature.

With all that said, we wish to reassure you that it is possible to work safely with the Registry. We will explain later how to back up the Registry itself-something that even novices might want to try, just in case the Registry ever gets corrupted.

Route to the Registry

To start working with the Registry, launch the Registry Editor in one of a few ways. In Vista, click Start, type regedit and select the entry from the list that is displayed. In XP, click Start, choose Run and type regedit into the dialogue box and click OK. Alternatively in either operating system hold down the Windows key and tap R simultaneously before typing regedit and pressing Enter.

In Vista it may be necessary to click Continue at the User Account Control box, if this is displayed. Once the Registry Editor has loaded, the similarity to Windows Explorer should be immediately apparent. The various components of the Registry are displayed in a tree-like structure in the left-hand panel, much like Explorer's folder display, while additional content is displayed to the right.

Registry rhymes

The terminology surrounding the Registry can be confusing, so it is good idea to familiarise yourself with a number of key terms before proceeding.

There are five main entries in the left-hand panel. These are referred to as hives, and each is concerned with the storage of different types of settings. The HKEY _CLASSES_ROOT hive is mainly used to store information about file associations, and HKEY _CURRENT_USER holds the settings of the user currently logged into Windows.
HKEY LOCAL MACHINE is used to store information about installed hardware and software and these settings are applied to all users, while HKEY _USERS comprises links to sections of HKEY _CURRENT _USER. Very little infonnation is stored in HKEY CURRENT CONFIG and that which it does contain relates to the current system configuration, with infOimation drawn from sub-sections of HKEY LOCAL MACHINE.

Expand one of the hives by clicking the plus sign alongside, and a series of folders is displayed - these are known as keys. These can contain further sub-keys. leons appearing in the right-hand pane are known as values, and these come in various types including String, Binary, DWORD and Expandable String.

The right-hand pane is split into three colunms, the first of which, labelled Name, simply indicate what the value is called. The Type column show the type that has been assigned to a value, while the Data column shows the setting that has been applied to a value. Depending on the type of value the Data column may contain a path, a number, or a word. It is also possible for a value to have no setting - indicated by the presence of the words 'value not set'. This should not be taken to mean that the value in question is not needed as the lack of data should be regarded as a setting in its own right. Software may check this Registry and perform a particular way if the value has no data, but perform differently is data has been assigned to it. It may also be the case that problems arise if the value is not found to be present.


Working with Registry

When editing the Registry it is vitally important that you are certain of any changes, additions or deletions you make. If you are unsure of anything, double-check and, if in doubt, leave well alone. Registry editing is potentially dangerous, and it is easy to turn a working computer into an unusable mess with one false step. Before implementing planned changes backing up all or part of the Registry is highly recommended. This can be achieved in a couple of ways.

The first option is to create a backup of a sub-key, safeguarding the data it contains. Right-click a sub-key and select the Export option from the menu that appears. In the dialogue box that appears, enter a meaningful name for the backup, ensure that Registration Files (* .reg) is selected from the 'Save as type' menu and then click OK., The backup file will be created (it will usually happen very quickly).

If need be, backups can be reinstated by right-clicking the .reg file created above and selecting the Merge option. Before using this as the sole method of backing up the Registry, it is important to note that when .reg files are merged back into the Registry, they will not necessarily undo all the changes that have been made to a key; any data that has been deleted or changed will be restored to its previous state, but anything that has been added will not be deleted.

This is why it can be useful to back up hives in their entirety. To do so, right-click a key and select the Export option as mentioned before. This time, ensure that Registry Hive Files is selected from the 'Save as type' menu. The file that is generated does not have a file extension, but it can be reimported into the Registry to undo any changes. Unlike .reg files which can be merged with the Registry, hives must be imported from within the Registry Editor. Click the File menu and select the Import option. Select Registry Hive Files (*. *) from the drop down menu and then navigate to and select the file that has been created before clicking Open. Click Yes to confirm the action and then OK once the operation is complete.

Backing up hives is by far the most secure means of backing up sections of the Registry because, when a backup is imported, all changes that have been made will be reversed. . If you have more than one computer running Windows Vista, for example, it is possible to make changes to the Registry on one machine, export the relevant keys and then copy the .reg file to another computer. The information stored in the file can then be imported into the second computer's Registry to save duplicate editing. Care should be taken to only use this method when working with keys that relate directly to Windows itself as the hardware and software installed on different computers is unlikely to be the same, and irrelevant Registry keys could lead to problems.

Finding your way

When navigating the Registry, it is easy to lose track of exactly where you are; not least because the highlight effect used to indicate which key is currently active can be difficult to see. But help is at hand in the form of the status bar. Just like Windows Explorer, the Registry Editor includes a small information panel at the bottom of the window which displays the address of the currently selected key. If this isn't visible, click the View menu and ensure that the Status Bar option is ticked.

Deleting unwanted keys and values is a simple matter of right -clicking the appropriate item and selecting the Delete option before confirming the action - renaming can be done in a similar fashion. To edit the data connected to a particular existing value, double-click it, make any required changes and click OK.

Should a Registry tweak require the creation of a new key, start by navigating to the key which is to act as the parent and then click Edit, then New followed by Key before entering a name and pressing Enter. If a new value needs to be created, click Edit then New and select the type of value to be created before typing a name and pressing Enter. The value can then be assigned a value by double-clicking it.

What next?

This Masterclass is intended as an introduction to working with the Registry, and there is not enough room to mention individual tweaks that can be applied. However, to get you started, use the Registry Editor to look at HKEY CURRENT USER\Software\Microsoft\ Windows\CurrentVersion\Run and HKEY LOCAL MACHINE\SOFTWARE\Microsoft\ Windows\CurrentVersion \Run. Here you'll find a list of programs configured to run automatically with Window simply delete any that are not required for accelerated startup times. This is a safe tweak but, as we've stressed throughout, do back up.

The tweaks and customisations that can be put in place by editing the Registry are virtually limitless, and plenty have been mentioned in the Workshops and No Problem sections of Computeractive over the years.