Why file systems matter on the A+ exam
The CompTIA A+ Core 2 exam (220-1102) doesn't treat file systems as a quick knowledge check. It tests them through troubleshooting scenarios where you have to identify the cause of an error and recommend the correct fix. The questions look practical because they are: a user gets an error copying a file, or you need to set up a shared drive between two operating systems, or you're asked why a specific Windows feature isn't available.
If you understand the five or six specific details CompTIA cares about, these questions are straightforward. If you studied file systems at the "FAT32 is older, NTFS is newer" level, you'll miss scenario questions that hinge on limits and features you can't bluff your way through.
FAT32: the 4 GB wall that still catches people
FAT32 (File Allocation Table 32) dates back to Windows 95 OSR2. It became the dominant file system through the Windows XP era and has been largely replaced for system drives and most storage since then. But it persists on USB drives and SD cards everywhere because it works with essentially every device on the planet — game consoles, digital cameras, car stereos, TVs, Linux machines, older Macs, anything with a USB port and a file system reader.
The exam tests one thing about FAT32 more than anything else: the maximum file size is 4 GB, and this is a hard limit. It's not a practical limitation that depends on drive size or Windows version. It's built into how FAT32 records file information. A single file that exceeds 4 GB cannot be stored on a FAT32 volume, period. Doesn't matter if the drive is 2 TB. Doesn't matter how much free space there is.
The exam scenario looks exactly like this: a user tries to copy a large video file or an ISO image to a USB drive and gets an error message saying "The file is too large for the destination file system." The correct diagnosis is that the drive is formatted as FAT32 and the file exceeds 4 GB. The correct solution is to reformat the drive as exFAT (if cross-platform compatibility is needed) or NTFS (if it's Windows-only), or split the file into smaller pieces (rarely the right answer in an exam context).
Additional FAT32 facts the exam occasionally tests: the maximum volume size is 2 TB, though Windows itself will only format a volume as FAT32 up to 32 GB using its built-in tools. FAT32 has no journaling, no permissions system, and no encryption support. Its only advantage is compatibility.
exFAT: the solution to FAT32's biggest problem
Microsoft introduced exFAT (Extended FAT) in 2006 specifically to solve the file size limitation of FAT32 for flash storage. The practical file size limit on exFAT is enormous — technically 128 petabytes — so you will never hit it with any real file. Drives up to 128 PB are also supported.
Like FAT32, exFAT has no permissions, no journaling, and no native encryption. What it adds is the ability to store files larger than 4 GB while maintaining broad compatibility across operating systems. Windows Vista SP1 and later support it natively. macOS 10.6.5 and later support it natively. Linux added mainline kernel support in version 5.4 (released 2019).
The exam scenario where exFAT is the correct answer: someone needs a USB drive or SD card that works on both Windows and macOS and needs to hold files larger than 4 GB. exFAT is the answer. NTFS would allow the large files but macOS can't write to NTFS without third-party software. FAT32 can't hold the large files. exFAT covers both requirements.
This is why cameras and drones format large SD cards as exFAT by default. The card gets connected to Windows for editing and to macOS for upload, and the video files are routinely larger than 4 GB. exFAT is the only file system that handles all of that without friction.
NTFS: what it supports that the others don't
NTFS (New Technology File System) has been the default for Windows system drives since Windows NT 3.1. Every Windows machine you've worked on ran its OS from an NTFS volume. The features that differentiate it from FAT32 and exFAT are also the ones the A+ exam tests most carefully.
File and volume size: Maximum file size is 16 TB. Maximum volume size is 256 TB. These come up in comparison questions but aren't the focus of NTFS exam coverage.
Journaling: NTFS keeps a change journal. Before writing data, it records what it's about to do. If a power failure or crash interrupts a write operation, Windows uses the journal to recover the file system to a consistent state on the next boot. FAT32 and exFAT have no journaling, which is part of why improperly removing a FAT32 drive mid-write can corrupt it.
Permissions: NTFS supports granular file and folder access control. This is a significant A+ topic in its own right and gets tested separately from the file system comparison questions.
Encryption: NTFS supports EFS (Encrypting File System) for per-file encryption. This is separate from BitLocker, which encrypts entire drives.
Compression: NTFS has built-in compression at the file or folder level. Compressed items appear in blue in Windows Explorer. This is transparent to applications — they read compressed files normally, and the file system handles the compression and decompression automatically.
NTFS cross-platform limitation: macOS reads NTFS drives natively but cannot write to them without third-party software like Paragon NTFS or Tuxera. Linux reads and writes NTFS through the ntfs-3g driver, which ships with most distributions. This limitation matters for drives shared between Windows and macOS — exFAT is typically better for that use case.
NTFS permissions: the deeper A+ exam topic
Permissions have enough exam coverage to justify treating them as their own subtopic. The exam asks scenario questions where you have to reason through what a user can or can't do based on their permission assignments.
The six standard NTFS permission levels, from most to least permissive: Full Control (read, write, modify, delete, change permissions, and take ownership of the file), Modify (read, write, delete — but cannot change permissions or take ownership), Read & Execute (open files and run executables), List Folder Contents (view what's inside a folder without opening files), Read (open and view file contents and properties), Write (create new files and write to existing ones).
Effective permissions are the combined result of all permissions assigned to a user — directly and through all group memberships. If a user is in Group A which has Read permission and Group B which has Modify permission, the effective permission is Modify, because the more permissive applies when combining Allow entries.
The rule the exam tests most often: Deny always overrides Allow. If a user has Allow: Modify from their personal account and Deny: Read from a group they belong to, the Deny wins. They cannot read the file regardless of the Allow entry. This is deliberately strict — administrators are generally advised to use Deny sparingly for this reason.
Inheritance: by default, subfolders and files inherit permissions from their parent. You can break inheritance through Advanced Security Settings and either copy the inherited permissions to explicit entries or remove them entirely. After breaking inheritance, changes to the parent no longer propagate down to that folder.
EFS vs BitLocker — the exam loves this distinction
Both are Windows encryption technologies. Both live on NTFS. They operate at completely different levels and the exam tests whether you know which one does what.
EFS (Encrypting File System) encrypts individual files and folders at the file system level. Encryption is tied to the user's certificate — when the authorized user opens a file, it's transparently decrypted. Anyone else, including other administrators, sees encrypted content. Encrypted files and folders appear green in Windows Explorer. EFS is available on Windows Pro, Enterprise, and Education editions. It is not available on Windows Home — this distinction appears in exam questions.
The critical EFS fact: the encryption certificate must be backed up. Lose the certificate and you lose access to the encrypted files permanently, even as an administrator, even if you know the password. Data Recovery Agents (DRAs) can be pre-configured by an administrator to allow admin recovery, but this must be done before encryption is applied. If you set up EFS without a DRA and then delete the user account, those files are gone.
BitLocker encrypts the entire drive volume, not individual files. It requires a TPM (Trusted Platform Module) chip or a USB startup key. When a BitLocker-protected drive is removed from a machine and connected elsewhere, the data is unreadable without the BitLocker recovery key. This makes it effective against the physical theft scenario — someone takes the drive out of a stolen laptop and connects it to another machine.
The scenario question the exam uses repeatedly: "A laptop is stolen. The hard drive is removed and connected to another computer. Which technology would prevent the attacker from reading the data?" The answer is BitLocker. EFS protects files against other users on the same machine but not against someone with physical access who removes the drive and boots their own OS without authenticating through Windows.
Converting file systems
The A+ exam tests one file system conversion scenario specifically: converting FAT32 to NTFS without losing data. The command is convert C: /fs:ntfs run from an elevated command prompt. This converts in-place without formatting the drive — the data stays intact.
There is no built-in Windows command to convert NTFS back to FAT32. If you need to go that direction, you back up the data, format the drive as FAT32, and restore. Third-party tools exist but they're not on the exam.
The format command formats a drive and erases all data. The exam distinguishes between quick format (marks sectors as available without writing zeros, data is technically recoverable) and full format (writes zeros to every sector, verifies the surface for errors, data is not recoverable through normal means). Know the difference.
Quick reference for exam day
Error: "File is too large for the destination file system" — FAT32 drive, file over 4 GB. Fix: reformat as exFAT or NTFS.
Drive needed for Windows and Mac with large files — exFAT.
Windows system drive file system — Always NTFS. No exceptions.
Camera SD card for large video files, multiple OS — exFAT.
USB drive for a game console and Windows PC — Usually FAT32 (most consoles support FAT32; check the specific device).
Convert FAT32 to NTFS without data loss — convert C: /fs:ntfs from elevated command prompt.
File encryption per-file, tied to user account — EFS (NTFS feature, not available on Home edition).
Full drive encryption, protects against physical theft — BitLocker.
Deny permission rule — Deny always overrides Allow, regardless of other assignments.