VarAC 5.1.8 with VARA HF 4.6.3 was working perfectly for me. I upgraded to VarAC 6.0.8 and VARA HF 4.6.4 and now I get this on startup: 14:36:03 - Error: UNABLE TO DECODE DATA FROM . ABORTING. See VarAC.log for more info. In most cases a VARA packet from another QSO on the same frequency slipped into this QSO and corrupted the link. 14:36:15 - Error: UNABLE TO DECODE DATA FROM . ABORTING. See VarAC.log for more info. In most cases a VARA packet from another QSO on the same frequency slipped into this QSO and corrupted the link. 14:36:27 - Error: UNABLE TO DECODE DATA FROM . ABORTING. See VarAC.log for more info. In most cases a VARA packet from another QSO on the same frequency slipped into this QSO and corrupted the link. VarAC stops and relaunches VARA HF three times. VarAC will transmit fine, and I can see things decode in the VARA HF monitor window, but VarAC never decodes anything. This also happens with VarAC 5.1.8, so it may be related to VARA HF 4.6.4, but I have not tried downgrading that yet. VarAC.log looks like this: 11/10/2022 14:35:55 - Starting VarAC (V6.0.8) 11/10/2022 14:35:55 - OS: Microsoft Windows NT 6.2.9200.0 11/10/2022 14:35:55 - Debug mode disabled 11/10/2022 14:35:55 - FREQ Schedule off 11/10/2022 14:35:55 - Opening com port 11/10/2022 14:36:00 - Connecting VARA Main Modem Command interface... 11/10/2022 14:36:00 - Connecting VARA Main Modem KISS Command interface... 11/10/2022 14:36:00 - Connecting VARA Main Modem data stream... 11/10/2022 14:36:00 - Connecting VARA Monitor Modem Command interface... 11/10/2022 14:36:01 - Connecting VARA Monitor Modem data stream... 11/10/2022 14:36:02 - Failed to connect VARA Monitor modem 11/10/2022 14:36:02 - Connected to VARA modem 11/10/2022 14:36:02 - Setting Bandwith to 500Hz 11/10/2022 14:36:02 - Change frequency: to last frequency used before shutdown. 11/10/2022 14:36:03 - VarAC base directory: C:\VarAC_V6_0_8\ 11/10/2022 14:36:03 - VARA version: VARA HF v4.6.4 11/10/2022 14:36:03 - Error: UNABLE TO DECODE DATA FROM . ABORTING. See VarAC.log for more info. In most cases a VARA packet from another QSO on the same frequency slipped into this QSO and corrupted the link. 11/10/2022 14:36:03 - Input string was not in a correct format. at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info) at System.Convert.ToInt32(String value) at VarAC.VarAC.<button_connect_varahf_Click>b__566_2() 11/10/2022 14:36:03 - Corrupted data that caused this: 
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 L L A c c e s s I p c  L L A c c e s s I p c (94e970b83fffcc18d44ae5233d87cba09798995f 11/10/2022 14:36:03 - Aborting Link... 11/10/2022 14:36:03 - Restarting VARA modem 1/2 11/10/2022 14:36:03 - Disconnecting VARA modem... 11/10/2022 14:36:03 - Disconnected! 11/10/2022 14:36:03 - Error in mailbox_send_outbox_thread 11/10/2022 14:36:03 - Error: Unable to read data from command stream of VARA modem. Disconnecitng modem command stream. 11/10/2022 14:36:03 - Thread was being aborted. at System.Threading.Thread.SleepInternal(Int32 millisecondsTimeout) at System.Threading.Thread.Sleep(Int32 millisecondsTimeout) at VarAC.VarAC.<button_connect_varahf_Click>b__566_4() 11/10/2022 14:36:03 - Thread was being aborted. at System.Net.UnsafeNclNativeMethods.OSSOCK.recv(IntPtr socketHandle, Byte* pinnedBuffer, Int32 len, SocketFlags socketFlags) at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags, SocketError& errorCode) at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags) at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) at VarAC.VarAC.<button_connect_varahf_Click>b__566_0() 11/10/2022 14:36:13 - Connecting VARA Main Modem Command interface... 11/10/2022 14:36:13 - Connecting VARA Main Modem KISS Command interface... 11/10/2022 14:36:13 - Connecting VARA Main Modem data stream... 11/10/2022 14:36:13 - Connecting VARA Monitor Modem Command interface... 11/10/2022 14:36:14 - Connecting VARA Monitor Modem data stream... 11/10/2022 14:36:15 - Failed to connect VARA Monitor modem 11/10/2022 14:36:15 - Connected to VARA modem 11/10/2022 14:36:15 - Setting Bandwith to 500Hz 11/10/2022 14:36:15 - Error: processing Modem data stream: Thread was being aborted. at VarAC.VarAC.<button_connect_varahf_Click>b__566_2() 11/10/2022 14:36:15 - Error: UNABLE TO DECODE DATA FROM . ABORTING. See VarAC.log for more info. In most cases a VARA packet from another QSO on the same frequency slipped into this QSO and corrupted the link. 11/10/2022 14:36:15 - Unable to read data from data stream of VARA modem. Disconnecitng modem data stream. 11/10/2022 14:36:15 - Input string was not in a correct format. at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info) at System.Convert.ToInt32(String value) at VarAC.VarAC.<button_connect_varahf_Click>b__566_2() 11/10/2022 14:36:15 - Restarting VARA modem 2/2 11/10/2022 14:36:15 - Corrupted data that caused this: 
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 L L A c c e s s I p c  L L A c c e s s I p c (94e970b83fffcc18d44ae5233d87cba09798995f 11/10/2022 14:36:15 - Aborting Link... 11/10/2022 14:36:15 - Disconnecting VARA modem... 11/10/2022 14:36:15 - Disconnected! 11/10/2022 14:36:15 - VARA version: VARA HF v4.6.4 11/10/2022 14:36:15 - Error: Unable to read data from command stream of VARA modem. Disconnecitng modem command stream. 11/10/2022 14:36:15 - Error in mailbox_send_outbox_thread 11/10/2022 14:36:15 - Error: processing Modem data stream: Thread was being aborted. at VarAC.VarAC.<button_connect_varahf_Click>b__566_2() 11/10/2022 14:36:15 - Thread was being aborted. at System.Threading.Thread.SleepInternal(Int32 millisecondsTimeout) at System.Threading.Thread.Sleep(Int32 millisecondsTimeout) at VarAC.VarAC.<button_connect_varahf_Click>b__566_4() 11/10/2022 14:36:15 - Unable to read data from data stream of VARA modem. Disconnecitng modem data stream. 11/10/2022 14:36:15 - Thread was being aborted. at System.Threading.WaitHandle.WaitOneNative(SafeHandle waitableSafeHandle, UInt32 millisecondsTimeout, Boolean hasThreadAffinity, Boolean exitContext) at System.Threading.WaitHandle.InternalWaitOne(SafeHandle waitableSafeHandle, Int64 millisecondsTimeout, Boolean hasThreadAffinity, Boolean exitContext) at System.Threading.WaitHandle.WaitOne(Int32 millisecondsTimeout, Boolean exitContext) at System.Windows.Forms.Control.WaitForWaitHandle(WaitHandle waitHandle) at System.Windows.Forms.Control.MarshaledInvoke(Control caller, Delegate method, Object[] args, Boolean synchronous) at System.Windows.Forms.Control.Invoke(Delegate method, Object[] args) at VarAC.VarAC.write_command_stream_log(String msg) at VarAC.VarAC.<button_connect_varahf_Click>b__566_0() 11/10/2022 14:36:25 - Connecting VARA Main Modem Command interface... 11/10/2022 14:36:25 - Connecting VARA Main Modem KISS Command interface... 11/10/2022 14:36:25 - Connecting VARA Main Modem data stream... 11/10/2022 14:36:25 - Connecting VARA Monitor Modem Command interface... 11/10/2022 14:36:26 - Connecting VARA Monitor Modem data stream... 11/10/2022 14:36:27 - Failed to connect VARA Monitor modem 11/10/2022 14:36:27 - Connected to VARA modem 11/10/2022 14:36:27 - Setting Bandwith to 500Hz 11/10/2022 14:36:27 - Error: UNABLE TO DECODE DATA FROM . ABORTING. See VarAC.log for more info. In most cases a VARA packet from another QSO on the same frequency slipped into this QSO and corrupted the link. 11/10/2022 14:36:27 - Input string was not in a correct format. at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info) at System.Convert.ToInt32(String value) at VarAC.VarAC.<button_connect_varahf_Click>b__566_2() 11/10/2022 14:36:27 - Corrupted data that caused this: 
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 L L A c c e s s I p c  L L A c c e s s I p c (94e970b83fffcc18d44ae5233d87cba09798995f 11/10/2022 14:36:27 - Aborting Link... 11/10/2022 14:36:27 - VARA version: VARA HF v4.6.4