diff --git a/CollabVMAgent/VirtIOSerial.cs b/CollabVMAgent/VirtIOSerial.cs
index 162ed63..85025a5 100644
--- a/CollabVMAgent/VirtIOSerial.cs
+++ b/CollabVMAgent/VirtIOSerial.cs
@@ -54,6 +54,20 @@ namespace CollabVMAgent
                     if (readCancel.IsCancellationRequested) return;
                     Thread.Sleep(READ_INTERVAL);
                     ReadFile(viohnd, sizebuf, 4, out read, IntPtr.Zero);
+                    var err = Marshal.GetLastWin32Error();
+                    if (err != 0)
+                    {
+#if DEBUG
+                        Console.WriteLine($"Got error {err} while trying to read from serial port");
+#endif
+                        switch (err)
+                        {
+                            case 6:
+                                CloseHandle(viohnd);
+                                viohnd = CreateFile(DevicePath, FileAccess.ReadWrite, 0, IntPtr.Zero, FileMode.Open, FileAttributes.Normal, IntPtr.Zero);
+                                break;
+                        }
+                    }
                 }
                 uint size = BitConverter.ToUInt32(sizebuf, 0);
 #if DEBUG
@@ -131,7 +145,7 @@ namespace CollabVMAgent
 
         }
 
-        [DllImport("setupapi.dll", CharSet = CharSet.Auto)]
+        [DllImport("setupapi.dll", CharSet = CharSet.Auto, SetLastError = true)]
         static extern IntPtr SetupDiGetClassDevs(
             ref Guid ClassGuid,
             IntPtr Enumerator,
@@ -174,7 +188,7 @@ namespace CollabVMAgent
         [DllImport("kernel32.dll", SetLastError = true)]
         static extern bool ReadFile(IntPtr hFile, [Out] byte[] lpBuffer, uint nNumberOfBytesToRead, out uint lpNumberOfBytesRead, IntPtr lpOverlapped);
 
-        [DllImport("kernel32.dll")]
+        [DllImport("kernel32.dll", SetLastError = true)]
         static extern bool WriteFile(IntPtr hFile, byte[] lpBuffer, uint nNumberOfBytesToWrite, out uint lpNumberOfBytesWritten, IntPtr lpOverlapped);
 
         [DllImport("kernel32.dll", SetLastError = true)]