Mutex gets ObjectDisposedException

[TomPel]

I have various processes that are all logging to the same file using the same
function. In order to ensure nobody logs at the same time, I am using mutex.
The code I am using is listed below:

mut.WaitOne()
Dim l_fstream As New StreamWriter(l_logfile, True)
l_fstream.WriteLine(stringtolog)
l_fstream.Flush()
l_fstream.Close()
mut.ReleaseMutex()

The code seems to work fine, except every now and then I get an
ObjectDisposedException. To recover from this exception, inside a catch
statement I am setting mut to a new mutex. I searched my code and other than
declaring Mut in the beginning of the class, I am not accessing Mut in any
other ways.

Does anybody have any idea what would cause the mutex to get disposed? I
have a workaround, but I'm really trying to find the root cause to this
exception.

Thanks!