Safely edit the Windows Registry

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. Icons 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 columns, 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 dropdown 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. Additional information about how to create and restore a backup of the Registry can be found on the Microsoft website.

However, .reg files are not entirely redundant. 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.