If Outlook refuses to start and throws the message «No se puede abrir el conjunto de carpetas» (it often appears in English as «The set of folders cannot be opened»), the issue usually comes down to one of three things: a damaged profile, a corrupted Navigation Pane, or an add-in interfering with startup. And yes, it’s especially frustrating because the warning explains nothing—like those errors that seem written for humans… but by robots.
The good news is that, without changing half of Windows or blindly reinstalling Office, there are several fairly straightforward ways to regain access. Below are three methods, ordered from least to most “surgical”, so you can try the one that best fits your situation.
Reset the Outlook Navigation Pane (the fastest option)
Before getting into advanced settings, it’s worth tackling one of the most common culprits: the Navigation Pane. This area—where your folders, favorites, and mailbox structure appear—can become corrupted and cause Outlook to freeze right at launch. Resetting it is often the cleanest fix when the problem shows up overnight.
The process is simple, but there’s one requirement: Outlook must be completely closed. Make sure it isn’t still running in the background. Then open the Windows Run dialog with Win + R (or search for “Run” from the taskbar) and enter this command:
Outlook.exe /resetnavpane
Click OK and, once it finishes, open Outlook normally from the Start menu, a desktop shortcut, or the taskbar. This detail matters: don’t reopen it from “Run” for this check. If the error is gone, you’ve found the cause—the Navigation Pane was in a bad state and Outlook has rebuilt it.
Still seeing the same message? Then it’s time to move on to the two causes that tend to be more troublesome: add-ins and the profile.
Start Outlook in Safe Mode and disable add-ins
Add-ins can be a double-edged sword. On one hand, they add useful features; on the other, it only takes one to break after an update, a permissions change, or a bad interaction for Outlook to fail before it even loads. In these cases, Safe Mode is your best friend because it starts Outlook with only the essentials, reducing interference.
With Outlook closed, open Run again (Win + R) and type:
Outlook.exe /safe
Outlook should open in Safe Mode. It may ask you to choose a profile: select the default profile, usually named Outlook. If Windows can’t find “Outlook.exe”, the original guide recommends using the full path to the executable; by default, it’s typically under Program Files > Microsoft Office.
Once you’re in, sign in to your account if prompted. Then go to File > Options and, in the left panel, select Add-ins. At the bottom you’ll see add-in management; next to the COM Add-ins dropdown, click Go… to open the list.
Now for the practical part: untick all enabled add-ins to disable them. Confirm with OK. And here’s another important note: to check the result, don’t reopen Outlook from the Run dialog. Close it and open it normally from Start or your usual shortcut.
If Outlook opens again with add-ins disabled, you know what comes next: re-enable them later, calmly (one by one), to find the one that was causing the issue. Because, let’s be honest, the “culprit” almost never confesses on its own.
Recreate the profile via the Registry (the most drastic fix)
If the two methods above don’t solve the problem, it’s very likely your Outlook profile is damaged. In that scenario, the approach suggested by the source is to delete the profile information from the Windows Registry so Outlook can regenerate it.
This step requires extra care: the Registry Editor isn’t forgiving. The guide stresses not to delete anything outside the folders indicated, since removing the wrong keys can make the system unstable. It also recommends making a backup via File > Export… before changing anything, so you have a snapshot of the current configuration.
To begin, search for regedit in the taskbar and open the Registry Editor. If Windows asks for confirmation, accept. In the left panel, expand HKEY_CURRENT_USER and then open Software. From there, navigate this path:
Microsoft > Office > 16.0 > Outlook > Profiles
Note the number: the source points out that 16.0 can vary depending on the version of Outlook you have installed, so you may see a different value.
Inside Profiles, it’s common to see a folder called Outlook. The procedure is to delete the folders you see in this section (for example, “Outlook”) by right-clicking and selecting Delete. If no folder appears, the guide itself suggests trying the other methods instead.
After deleting the profile, restart your PC and open Outlook again to see whether the error is gone. It’s a more aggressive measure than the previous ones, but when the profile is corrupted, it’s also the most direct way to force Outlook to rebuild its basic configuration.
In short, if your priority is to get access back as quickly as possible, the most sensible order is: Navigation Pane reset, Safe Mode and add-ins, and if nothing works, recreate the profile via the Registry. That way you avoid unnecessary changes and start with what most often fails in the Microsoft ecosystem—which can be as powerful as it is… temperamental.
