# EXC_GUARD The process violated a guarded resource protection, often related to file descriptors. ## Discussion There are multiple types of guarded system resources, however most guarded resource crashes are from guarded file descriptors, which have the `GUARD_TYPE_FD` value in the `Exception Subtype` field. The operating system marks a file descriptor as guarded so that normal file descriptor APIs can’t modify them. For example, if an app closes the file descriptor used to access the SQLite file backing a store, could mysteriously crash much later on. The guard file description identifies these problems when they happen, making them easier to identify and address. The `Exception Message` field contains the specific violation: - `CLOSE`: The process attempted to invoke `close()` on a guarded file descriptor. - `DUP`: The process attempted to invoke `dup()`, `dup2()`, or `fcntl()` with the `F_DUPFD` or `F_DUPFD_CLOEXEC` commands on a guarded file descriptor. - `NOCLOEXEC`: The process attempted to remove the `FD_CLOEXEC` flag from a guarded file descriptor. - `SOCKET_IPC`: The process attempted to send a guarded file descriptor through a socket. - `FILEPORT`: The process attempted to obtain a Mach send right for a guarded file descriptor. - `WRITE`: The process attempted to write to a guarded file descriptor. The `Exception Message` field also identifies the specific guarded file descriptor that the process attempted to modify. To understand the context triggering this exception, consult the backtrace of the crashed thread. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)