A very annoying situation: I'm getting a STATUS_ACCESS_VIOLATION exception in about 2 out of 3 operations performed under cygwin/x. An operation in this context can be starting an x application (e.g., xterm) or running some command from within emacs (e.g., diff or latex). In attempt to isolate the problem, I reinstalled cygwin from scratch using the default settings of setup.exe + xorg-server, xinit, xorg-docs, and X-start-menu-icons. Next, I open a cygwin bash window and then invoke startxwin.exe . The x-server is invoked but an xterm window does not open and the following message appears: ***message begins*** 4 [main] xterm 7156 exception::handle: Exception: STATUS_ACCESS_VIOLATION 1449 [main] xterm 7156 open_stackdumpfile: Dumping stack trace to xterm.exe.s tackdump 4 [main] xterm 7996 exception::handle: Exception: STATUS_ACCESS_VIOLATION 1356 [main] xterm 7996 open_stackdumpfile: Dumping stack trace to xterm.exe.s tackdump 4 [main] xterm 5268 exception::handle: Exception: STATUS_ACCESS_VIOLATION 647 [main] xterm 5268 open_stackdumpfile: Dumping stack trace to xterm.exe.s tackdump 5 [main] xterm 4316 exception::handle: Exception: STATUS_ACCESS_VIOLATION 739 [main] xterm 4316 open_stackdumpfile: Dumping stack trace to xterm.exe.s tackdump 2 [main] xterm 2752 exception::handle: Exception: STATUS_ACCESS_VIOLATION 1123 [main] xterm 2752 open_stackdumpfile: Dumping stack trace to xterm.exe.s tackdump 5 [main] xterm 3220 exception::handle: Exception: STATUS_ACCESS_VIOLATION 1260 [main] xterm 3220 open_stackdumpfile: Dumping stack trace to xterm.exe.s tackdump 6 [main] xterm 6752 fork: child -1 - died waiting for longjmp before initi alization, retry 0, exit code 0x600, errno 11 xterm: Error 29, errno 11: Resource temporarily unavailable Reason: spawn: fork() failed ***message ends*** The content of the resulting xterm.exe.stackdump file: ***content begins*** Exception: STATUS_ACCESS_VIOLATION at eip=610202F7 eax=00C500F8 ebx=612294A4 ecx=755F783F edx=002620F0 esi=00000000 edi=0022FA14 ebp=61020A10 esp=0022C7E4 program=C:\cygwin\bin\xterm.exe, pid 3220, thread main cs=001B ds=0023 es=0023 fs=003B gs=0000 ss=0023 Stack trace: Frame Function Args End of stack trace ***content ends*** This phenomenon (or a similar one where I'm getting only 1 or two lines of the exception and xterm does open) is very common: it happens in about 2 out of 3 startxwin.exe invocation attempts. The same thing happens when I'm trying to open a new xterm window from an existing one. I'm using Windows 7 (32 bits). This is probably a relevant info as my old laptop (with Windows XP) works fine (once again with a fresh installation of cygwin + cygwin/x). I'm somewhat surprised that this problem was not reported before since I know that my office mate suffers from it as well (she is also using Windows 7 32 bits). I've already tried to discuss this problem in the cygwin mailing list (see http://cygwin.com/ml/cygwin/2010-04/msg00740.html) without a positive resolution. Thinking about it some more, I now understand that this problem occurs only under x, so I hope that this is the right mailing list. Any suggestions? The output of cygcheck -s -v -r and the content of /var/log/XWin.0.log are attached.