When macOS user wants to remove or create a partition on their disk drives, they typically have to use the Boot Camp Assistant—a tool that helps with anything that involves partitions. Usually, it works swimmingly, but there are instances where you may encounter an error that prevents you from accomplishing what you set out to do. One such issue is the “The startup disk cannot be partitioned or restored to a single partition” error that appears in the app occasionally.
What Is The “The Startup Disk Cannot Be Partitioned Or Restored to A Single Partition” Error?
The “The startup disk cannot be partitioned or restored to a single partition” error appears when you launch Boot Camp Assistant and attempt to do anything to a partition. More specifically, it appears when you click the Continue button that often appears on the app. Though it’s not clear why it happens, there are speculations as to where the issue comes from.
Here are some examples of the potential reasons:
- You’re partitioning the startup disk into multiple parts and not just a single partition.
- The startup disk is corrupted or has something wrong with it, hardware-wise.
- Your computer has insufficient disk space.
Naturally, the corresponding solution will depend on the root cause. With that said, here’s how you can fix the error depending on the reason why it happened in the first place. Let’s start with the solution for the first cause.
Solution #1: Delete Your Other Partitions
Your startup disk can usually only be partitioned into one. If you partition it into multiple parts, there are bound to be errors, such as the “The startup disk cannot be partitioned or restored to a single partition” error. To fix this, you must delete the other partitions that you can afford to lose. Here’s what you need to do to pull it off:
- Click the Apple icon at the top-left corner of your screen.
- Select About This Mac from the dropdown menu.
- A popup window will appear where you can find several tabs. Go to the Storage tab.
- There will be a bar diagram there consisting of numerous colors. When you hover over the colored bars, their names appear. The partitions should be indicated here. Check whether there are multiple partitions in your disk.
- If there are multiple partitions, open Finder. If there isn’t, then proceed to the next solution.
- On the left sidebar of Finder, click the Applications option.
- Find and open the Utilities folder.
- Double-click on Disk Utility.
- From the left sidebar of the app, right-click on the data partition you wish to delete.
- Select Delete [Name] Volume
Solution #2: Repair Your Startup Disk
The next reason is that your startup disk might have an issue with its hardware. Thankfully, you can also fix this using the same app you used in the previous solution, Disk Utility. Here’s how you can repair your startup disk with Disk Utility:
- Open the Disk Utility program.
- Find your startup disk from the left side of the interface.
- Select the First Aid button from the menu bar of the window.
- Click Run to confirm your action.
- Wait for a few minutes as the system repairs your startup disk.
That should fix not only the issue that’s causing the error message but also other issues that might be plaguing the startup disk of your macOS computer. If it didn’t, then perhaps the issue lies in the current lack of disk space on your computer.
Solution #3: Free up Space on Your Startup Disk With Mac Cleaner
As stated in the earlier sections, one of the main reasons why you’re encountering the “The startup disk cannot be partitioned or restored to a single partition” error is that your computer lacks disk space. Obviously, the way to fix it is by simply freeing up space on your storage disk. There are several ways to go about this, but most of them require a bit of time and effort, which can be a pain in the neck. If you wish to resolve this issue more quickly, we suggest using Mac Cleaner.
Mac Cleaner is a cleaner app that mainly aims to delete unnecessary files. Basically, its main purpose is to free up space on your computer, which is ideal for your goal. With that in mind, here’s how you can use Mac Cleaner:
Step #1: Download, Install, and Set Up Mac Cleaner
The first thing you must do is get the software. To do that, you must open any browser on your computer and visit the Mac Cleaner download site. There, you’ll find a Download Now button. Click that button to download a DMG file, which would be the software installer. Open that file to run the installer then simply follow the instructions from start to finish.
Step #2: Choose a Cleaner Module
Mac Cleaner has six modules in total, and these are (1) Clean Up Junk, (2) Delete Large Files, (3) Delete Duplicate Files, (4) Erase Private Data, (5) Speed Up Your Mac, and (6) Manage Apps & Extensions. Every module has varying functionalities, but only the first three will be useful for fixing the “The startup disk cannot be partitioned or restored to a single partition” as they can free up space on your computer. Here’s a look at what each of those three modules can do:
- Clean Up Junk can scan and delete files that the system considers junk from your computer. These may include files like the System Junk, App Junk, Trash Bin, iOS Junk, iTunes Junk, Unused Disk Images, and Downloads.
- Delete Large Files detects any file that has a size exceeding or equal to 50MB, regardless of file type.
- Delete Duplicate Files looks for files that have more than one copy on your Mac, or in other words, duplicates.
To proceed, simply select the module you wish to use by clicking on it from the left side of the interface.
Step #3: Scan Your Mac for Files
The third step is all about scanning your macOS computer for the appropriate files. The files may vary according to the module, and so do the steps. With that in mind, here’s what you must do to scan for files using the cleaning modules:
- Clean Up Junk: The software will have two sides, Quick Clean and Deep Clean. Quick Clean scours the computer for System Junk, App Junk, Trash Bin, and iTunes Junk. Meanwhile, Deep Clean scans Downloads, iOS Junk, and Unused Disk Images on top of the aforementioned file types. Select between these two and click the Scan button.
- Delete Large Files: Click the Scan button immediately.
- Delete Duplicate Files: To the left of the Select a File Directory field at the center of the interface, you’ll find a button that says Browse. Click that Browse button. When a popup window appears, navigate to the folder you want to scan for duplicates and click Open. Once you’ve specified a directory, simply click the Scan button.
Step #4: Select a File/s
Next, you must select the files you want to delete. Similar to the previous step, the way to do it will vary according to the module. For Delete Large Files and Delete Duplicate Files modules, you get a list right away consisting of images, videos, documents, songs, folders, etc. from which you must select items. You can select an item by clicking its corresponding checkboxes. There’s also a Select All option if you wish to delete all items included in the list.
As for the Clean Up Junk module, the list consists of categories like System Junk, Downloads, Trash Bin, Unused Disk Images, and more. You must select a category first. Upon doing so, a new list will appear on the right side which consists of actual files. At that point, you simply have to select items normally like how you will in the previous modules.
Step #5: Delete the File/s
Once you’ve selected all the files you want to delete that you think you no longer need, simply click the blue button at the top-right corner of the window which should either say Clean or Delete. Then, wait for a few minutes for it to delete the files.
By deleting unnecessary files and freeing up disk space on your computer, you should be able to fix the “The startup disk cannot be partitioned or restored to a single partition” error. If you do this regularly, you can also minimize the likelihood of the error ever appearing again, which is always a good outcome. All of this is possible with Mac Cleaner.
Final Words
It might be a bit of a hassle, but you’ll rarely need to create or remove a partition in your computer anyway. So, while it may take a lot of your time to fix the “The startup disk cannot be partitioned or restored to a single partition” error, this will most likely be a one-time thing. Even if it isn’t, you now at least know how to resolve the issue, which should take much less time considering you’ve already gone through the error once. That’s particularly true if you use Mac Cleaner as it can drastically speed up the process, especially if the problem lies in the lack of storage space.
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