Software & Apps MS Office Letting Outlook Express Compact Messages When It Asks by Heinz Tschabitscher Writer A former freelance contributor who has reviewed hundreds of email programs and services since 1997. our editorial process Heinz Tschabitscher Updated on February 06, 2020 Tom Merton / Getty Images MS Office Outlook Word Excel Powerpoint Tweet Share Email When you close Outlook Express, a message pops up and states To free up disk space, Outlook Express can compact messages. This may take up to a few minutes... The message is vague, which makes it no less alarming. What's going on? Does Outlook Express want to delete your old emails? Or is this a virus masquerading as something legit? What Should You Do? If you do not have to leave and shut down the computer immediately: Click OK.Wait for the compacting process to finish. Don't Interrupt the Process It is important that the process of compacting folders is not interrupted. If allowed to finish, compacting ensures that your Outlook Express runs smoothly and disk space is not wasted in too excessive a manner. What to Do If Your Messages Disappear If the compaction process was interrupted or the Outlook Express message store files get corrupted for another reason, Outlook Express may start to empty folders. Your messages probably are not gone, however. You can build a safeguard into the Outlook Express compaction process with a patch that backs up all data before compacting. To recover from automatically created backup copies: Make sure Outlook Express is not running.Open the Recycle Bin on your Windows Desktop.Locate the ".bak" files corresponding to the Outlook Express folders you want to recover.The ".bak" file will be named like the folder in Outlook Express.To restore a folder called "Archive", look for "Archive.bak", for example.Click on the ".bak" file with the right mouse button.Select Restore from the menu.Open your Outlook Express store folder in Windows Explorer.Drag and drop the ".dbx" file corresponding to the Outlook Express folder you want to recover to your Desktop.In the Outlook Express store folder, click on the ".bak" file to be recovered with the right mouse button.Select Rename from the menu.Change the ".bak" file extension to ".dbx".If the file was called "Archive.bak", for example, make sure it is named "Archive.dbx" now.Open Outlook Express.If your emails have been recovered, delete the ".dbx" file you moved to the Desktop. Even if you had not yet installed the patch, message recovery could be easy: Exit Outlook Express.Look in your Windows Recycle Bin for a .dbx file corresponding to the folder from which mail is missing.Restore the .dbx file.Start Outlook Express. To recover mail from an already corrupted message store, use one of the Outlook Express recovery tools. But why is compacting necessary anyway? What Does Compacting Messages Mean, and What Happens? When you delete an email in Outlook Express, it is moved to the Deleted Items folder. The message disappears from its original folder, and when you empty the trash, it disappears from there, too. In neither case is the message removed from the file on your disk immediately, however. Editing files for this is a slow process, and you'd have to wait or experience Outlook Express responding slowly whenever you deleted a couple of emails. This is why deletion merely hides the messages from view. Of course, having all your deleted messages still on disk means a lot of space that can be reclaimed is wasted over time, and if Outlook Express has to keep track of too many obsolete messages this itself can mean a slowdown of certain actions. So Outlook Express tries to remove these deleted emails physically from time to time. This it calls "compacting." Every 100 times you close Outlook Express, you are asked to start that process. If This Process Is so Essential, Why Doesn't Outlook Express Do It on Its Own? Compacting folders from time to time is essential. Even more essential is that the process can be completed without interruption, however. If Outlook Express did the compacting in the background and automatically, you might notice a slowdown and try to quit Outlook Express. Compacting, Outlook Express would refuse to shut down, of course. In your frustration, you might kill the process and your messages could become corrupted. Compacting Folders Manually After deleting a host of messages and emptying the Deleted Items folder, you can compact your .dbx files manually to reclaim disk space immediately: Select File | Folder | Compact All Folders from the menu. Note that compacting manually will not reset Outlook Express's launch count. If you compress your folders manually before closing Outlook Express for the 100th time, it will still ask you to do its periodic cleanup. (It should not take too long in that case.) You can avoid that by resetting the count in the registry: Make sure you have just compacted Outlook Express's folders manually. Do not change the registry just to avoid compaction.Navigate to your Outlook Express settings in the Windows registry.Look for and double-click Compact Check Count.Enter "0".Click OK.Close the registry editor.