These are the most frequently encountered known issues. See also Missing ReactOS Functionality.
- 1 Audio
- 2 DirectX
- 3 Drivers
- 4 File Systems
- 5 Installation
- 6 Mouse
- 7 Multiprocessing
- 8 Network
- 9 Printing
- 10 Remote Procedure Call
- 11 Serial Port
- 12 USB
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.
- Forum discussion, AC97 and HD audio
- Forum discussion, Creative EAX Aureal 3D and others in old games
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.
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.
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.
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
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.
Executable files cannot be run from network shares. This is believed to be due to missing functionality in the cache subsystem in the kernel.
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.
The printing stack is incomplete. May be able to send raw ASCII text through parallel port, nothing else.
See also: Printing
Remote Procedure Call
Most Remote Procedure Call (RPC) client processes leak memory.
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.