Recently (during the last week?) I started to experience hangs of TB 19 UI just while reading emails. I attached VC++ and downloaded the proper symbols+sources and when the hang happens, VC shows this stack: ntdll.dll!_NtWriteFile@36() + 0x15 bytes ntdll.dll!_NtWriteFile@36() + 0x15 bytes > kernel32.dll!_WriteFileImplementation@20() + 0x4a bytes The rest of the stack trace is bogus, twice it showed a different crap, so I don't know where from this method is being called. ProcessExplorer says nothing.

Not much to go on :( Nothing coincidental happening in Error Console or Activity Manager?

Hmm.. it might be a bug in logging which I have turned on for POP3 service (break before call to _WriteFileImplementation shows): kernel32.dll!_WriteFileImplementation@20() + 0x45 bytes msvcr100.dll!_write_nolock(int fh=4, const void * buf=0x003bd3bc, unsigned int cnt=1) Line 332 + 0x2c bytes C msvcr100.dll!_write(int fh=4, const void * buf=0x003bd3bc, unsigned int cnt=1) Line 74 + 0xc bytes C msvcr100.dll!_flsbuf(int ch=10, _iobuf * str=0x00000004) Line 189 + 0xd bytes C msvcr100.dll!_fwrite_nolock(const void * buffer=0x00f15000, unsigned int size=1, unsigned int num=91, _iobuf * stream=0x720e2088) Line 194 + 0x7 bytes C msvcr100.dll!fwrite(const void * buffer=0x00f15000, unsigned int size=1, unsigned int count=91, _iobuf * stream=0x720e2088) Line 83 + 0x11 bytes C nspr4.dll!PR_LogFlush() Line 530 + 0x30 bytes C nspr4.dll!PR_LogPrint(const char * fmt=0x5c941610, ...) Line 522 + 0x5 bytes C > xul.dll!nsPop3Protocol::LoadUrl(nsIURI * aURL=0x0db5c888, nsISupports * __formal=0x00000000) Line 1072 + 0x16 bytes C++ PR_LogFlush could be the cause, since I have "append" in the list of modules and the file can easily become 7GB (Giga!) long. I think this is invalid then. I'll turn of logging and recheck.

Since I've turned off logging, I cannot reproduce. Closing as WONTFIX.

Does it flush the file to disk after each line? That could be a slowdown. But that may be needed for logging as the app could crash (instability may be the reason for enabling the log) and unflushed lines could be lost.

(In reply to :aceman from comment #4) > Does it flush the file to disk after each line? That could be a slowdown. > But that may be needed for logging as the app could crash (instability may > be the reason for enabling the log) and unflushed lines could be lost. sync module was not defined. I think it is flushing after some number of lines, since the NSPR log buffer is relatively small.