Is it possible to convert a file system without formatting?

Sometimes you may want to use data from a hard drive that is stored in a file system that isn’t compatible with your computer. I have encountered this problem when I moved from Mac to PC and again when I moved to Linux. The last thing you want to do is format the drive and lose all that data so it begs the question is it even possible to convert the hard drive without formatting it?

Yes, it is possible but it depends on the initial file system and the intended one as some formats are simpler to change than others. It is recommended to backup your data first which in itself could negate the need to change the file system, as you could back up the drive, reformat it and then transfer the data back. But there are situations where this isn’t practical so let’s take a look.

Lets look at what options are possible and how we can convert a file system without formatting it.


What is a file system?

A file system is essentially a database that contains the physical location of your data on a hard drive (or any type of data storage device). It gets its name from the fact that the database is organised in directories that can contain folders and files, kind of like a filing cabinet. if you think of me as an operating system like windows and my filing cabinet as my file system then my filing cabinet might be organised differently from yours but I only understand how to access filing cabinets organised in my way. So if you changed your filing cabinet to be organised like mine then I could access it and understand it. And that is essentially what we are talking about here.

File systems can be completely unique to a device or can be read by multiple operating systems and devices. An ATM will have a file system the same way your laptop does, whether it’s a PC or Mac or Linux or Chromebook or Raspberry pi, or any type of computer you can think of, there is a format of file system that it will prefer. It might even be exclusive to that system.

What is hard drive formatting?

Hard drive formatting is essentially the process of resetting the file system to make space available for a device to make use of it. It is often mistaken for deleting of data, but the data isn’t actually deleted when a hard drive is formatted, which is important to note because sometimes you might want the data to be actually deleted and formatting leaves the data accessible until it is completely written over.

A hard drive uses the file system as a way to store information about where data is stored on the drive. This is the information that is deleted, not the actual data itself.

There are different levels to formatting, typically a quick format will revert it back to the file system that is already in place, essentially resetting the hard drive so it is ready to receive new data. An advanced format will enable you to do several things like changing the file system (and losing the data) or partitioning the hard drive to have various file systems stored on it.

What is hard drive Partitioning

Hard drive partitioning is when you split the available space on a hard drive into smaller partitions or sections that have a unique assignment. These partitions have their own allocated space and identifying drive letters and can be in different file systems. Quite often you will see an operating system create a partition as a recovery drive so that if something goes critically wrong with the file system it boots from it can use the recovery partition to boot from instead and can repair the main partition from there.

Partitioning can be used for multiple reasons, for example, my laptop dual boots Windows and Linux but they both use different file systems so I have split my hard drive into two unique file systems, one for windows NTFS and one for Linux ext4. Neither system can work with the other but I can use this technique to run two different operating systems on my laptop where I cant fit in an extra hard drive.

Why would I need convert a file system?

Essentially converting a file system is changing it from one to another so that it can be used by different operating systems on different devices or even different operating systems on the same device like on my dual boot laptop.

There are several situations where a drive or drive partition may need to be converted to a different file system. The most common one is changing operating system. If for example, you decide that you have had enough of Macs and you buy a PC, you may be a bit disheartened when you plug in your hard drive that worked perfectly on your mac and find that your PC doesn’t even recognise it. Depending on which system you are moving to and from you may be able to read data and not write it or maybe you won’t even be able to read it, nether the less until you change the file system you won’t have full functionality of your hard drive.

You may not be changing the operating system but instead, the problem could be that you chose the wrong format, to begin with within the available ones on your operating system and are stuck within limitations. Say for example you format a thumb drive to FAT32 and you start filling it up with photos only to find a long vacation video won’t copy across. FAT32 has a 2GB file size limit. So maybe you need to change it to NTFS to exFAT instead. (Can you tell I’m speaking from experience?)

Should I convert a file system without formatting the hard drive?

Converting a file system is a complicated process and there can be a lot of errors along the way. Converting between OS-specific formats can be low risk, but changing between different OS-compatible formats is harder and higher risk. The risk we are talking about here is data loss, so if you are able to back up your data before you try then the risk is somewhat mitigated, but it still might not be the simplest solution. I would only recommend it if your hands are tied and there are no other options available to you.

The simplest and easiest way to do this is not to convert it but to extract all of your data and to reformat the drive and copy your data back to it. It takes longer but it is more secure and there is far less chance of losing data.

Pros and cons of converting a file system without formatting.

So lets look at the pros and cons before we get into it, this is an important step because data loss can be devastating, hours of work, memories, unfinished projects, etc.. can be lost. You have to ask yourself if its worth it.


  • You dont have to move data back and forth.
  • Saves time.
  • Makes drives accessable.
  • Can be very convinient.
  • Safe within OS specific formats (but not 100%)


  • You could lose data.
  • Unpredictable results.
  • Not the safest way.
  • Requires tech skills or additional software
  • Not possible in all formats
  • Could result in completely corrupted hard drive.

What file systems can I convert?

You can convert OS (operating system) specific file systems between each other easily using free software.

On Windows MiniTool Partion Wizard offers a free version that can be used to convert between FAT formats and NTFS. It can also convert a RAW file system to NTFS.

On MAC you can convert from HSF+ and HSF to APFS using the disk utility, however, there isn’t a built-in option to go the other way. This is because APFS is the latest file system Mac uses. There are third-party apps to do this but none of them can promise the prevention of Data loss so I don’t recommend them.

On Linux, there are several file systems to choose from but the most common are ext2, ext3 and ext4, These can be converted in the Linux terminal depending on what distro you use.

To change between OS there are options…

To change from Windows to Mac is possible but has a lot of steps. Currently, the only option is to convert from NTFS to HSF+ so if you are starting from FAT32 or went to end up with APFS then there are going to be multiple conversions.

The same is possible in reverse for Apple to Windows, from HSF+ to NTFS but you have the limitation of not being to reliably down convert from APFS, however, it is possible to convert directly to NTFS from APFS there is no guarantee of data retention and the technique involves formating and then recovering your data.

There are possible solutions for Windows to Linux and vice versa as well as Mac to Linux etc… though not every solution is possible and there are too many file systems to list!

How do I convert a hard drive file system?

It would be a very long article if I listed every possible way to convert file systems so instead I will advise you on how to research and execute the best possible solution.

2Firstly you need to establish exactly what type of hard drive file system you want to convert. If you are on Windows hit the windows key and type “disk management” press enter and you will be treated by a window that informs you about every drive available and its partitions. You can identify the disk you want using the letter allocated or by the disk number and description, for example, a thumb drive will be described as removable.

After the size of the disk, the file system is displayed. Make a note of this file system.

Now you need to know what file system you need to convert to. This can be complicated to figure out but searching “Best file system for [insert device and OS here]” should give you an answer.

Then it is simply a case of searching “how to convert NTFS to HFS+ on windows without data loss” for example, this states the format we currently have, the desired one and the operating system were doing it on and the fact we’re not looking to simply format the drive. In researching this article I have tried a dozen versions of this search and almost every time a software company has answered the question by recommending their software to complete the task. I would highly recommend looking up reviews for the software before downloading anything and ensuring you are on the actual website of the developer to avoid getting viruses.

One last comment is that quite often these programs come with additional programs and offers during the installation phase, be sure to watch out for these to avoid troublesome browser plugins and adware on your computer.

How can I convert a hard drive file system using partitions?

If your hard drive isn’t full it might be more convenient to partition the drive into two sectors that can be different file systems and then to transfer the data between them. There are tools to do this on each operating system, and different systems can format different file systems. So check for compatibility before you partition any disks and ensure that everything is backed up.

This method also depends on the fact that your os will be able to write to the new partition so you can transfer your data to it, or from the original file system. make sure to do your research on compatibility before using this technique, however, if done properly it is reversible provided you haven’t moved any data yet.

How can I access non compatable file systems on my PC?

Now I have continuously advised you to back up your data before converting it, but sometimes that requires accessing the data in the first place. If you have a Mac HFS+ drive and only a windows computer then how are you supposed to back up the data before converting the drive?

Luckily there are options for almost all operating systems and file systems. You will need to search for the relevant reader application for your OS. On my PC I use HSFexplorer to read data from my old mac drives. This means I can copy the data to a backup disk ensuring it is safe before I attempt to convert the drive itself.

Which program to use depends on the drive you want to read and the OS you’re working from but I have yet to be stuck without an option. This is why my preferred method of converting a hard drive is by saving the data elsewhere then reformatting the drive and copying the data back.