Known Issues

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Revision as of 21:31, 3 December 2018 by Middings (talk | contribs) (Audio: Mention AC97 audio. Note that HD Audio bus and UAA HD Audio class drivers are not yet implemented.)
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These are the most frequently encountered known issues. See also Missing ReactOS Functionality.


Code supporting audio is unstable. AC97 audio mostly works. Presently, ReactOS's audio targets features of Microsoft Windows XP and Server 2003.

HD Audio or use of multiple audio cards at the same time are not yet supported. The necessary HD Audio bus driver and Universal Audio Architecture (UAA) HD Audio class driver are not yet implemented.


DX9 functions but at this time uses ReactOS's OpenGL acceleration support with the Wine project's wrapper code to provide DX9 support.


Drivers, Built in

Only a basic set of drivers are provided by ReactOS. Drivers for additional devices and drivers tailored for devices such as high-performance video cards must be installed manually.

Drivers, Manual installation of

Manual installation of some drivers is not always possible. The ReactOS driver stack may be missing functions that a third-party driver requires for its installation.

Drivers, Software for installation of

Software that automates the installation of hardware device driver software usually fails. Install drivers manually.

File Systems


It works well (except for some minor glitches here and there, you can check BTRFS issues in JIRA to see if they get fixed and report if they are new). ReactOS can be installed on it.


ReactOS can read and write ext2. However, support is not yet complete enough to allow installation of ReactOS on ext2 file systems.


Well supported.


ReactOS can read NTFS. Write capability is being worked on. Much more debugging is required. Do not write on NTFS storage devices if any data on the device is valuable. NTFS support is not yet complete enough to allow installation of ReactOS on NTFS file systems.


UDF support (required for DVDs) is not yet bug free. May have problems when starting an executable file from UDF disc. May have to manually eject disc from drive.

Revision 74901 notes


Forum discussion


Why the ReactOS Project will not work on NTFS/ZFS/Reiser4/whatever right now


Installation from USB drives

Cannot install ReactOS from USB drives.


Installation, required file system for

ReactOS can only install on FAT32 and BTRFS file systems at this time. FAT32 support is mature, BTRFS support is experimental.


Mouse pointer speed adjustment

Mouse pointer speed adjustment is not supported at this time.


Mouse, USB device

See USB.


Multiple processors are not supported at this time. Even if the PC has multiple processors or multiple cores, ReactOS will use only one core.

However ReactOS can perform multiprocessing to allow many processes (programs) to run concurrently.


Network shares

Executable files cannot be run from network shares. This is believed to be due to missing functionality in the cache subsystem in the kernel.

Forum discussion

Built-in NIC drivers

ReactOS's network interface controller (NIC) driver support (i.e., Ethernet functionality) is only implemented for NICs based on the Realtek 8139 device. Clever people might be able to manually install the drivers for other NICs on their PCs. (There are no formal instructions to do this.)


Only Wired Equivalent Privacy (WEP) is supported at this time.

Forum discussion


The printing stack is incomplete. May be able to send raw ASCII text through parallel port, nothing else.

See also: Printing

Revision 75125 notes

Remote Procedure Call

Memory leak

Most Remote Procedure Call (RPC) client processes leak memory.

Forum discussion

Serial Port

Debugger connection

Debugger connection from target PC under test to host PC via null-modem cable consumes serial port COM1.


USB stack is not yet fully functional. Attached USB devices including USB keyboards, mice, and touch pads (even if built into a laptop) may prevent ReactOS from booting, cause a bug check if attached after ReactOS is booted, or not be recognized by ReactOS. Most USB keyboards and mice will not work with ReactOS. USB storage devices will not work properly.