I give up.   I just finished doing a windows recovery (reinstalled windows) and have same problem,   At this point I need some one like Joe Taylor, who knows the code and the exact conditions that could cause "Error in Sound Input".

Good Grief ! 
Now I've uninstalled all sound device drivers In Device Manage (verified void of drivers)
and tried it without drivers (before restarting) same thing ..."Error in Sound Input"
then restarted and verifier that drivers were automatically reinstalled....same thing "Error in Sound Input"
and all this with Settings:  RADIO = NONE and no cables connected to radio
simply clicking MONITOR causes "Error in Sound Input" message box
This would seem to confirm that internal sound card is not bad
Good Grief ! 

I Will try........ to delete my internal sound card.
However I plugged in a spare USB module and got same error.
Even further .......... I purchased a new USB sound device.... and cables.... got same error.
Remember.......  I set RIG to NONE and the decode of sample files works.

It is only when I click MONITOR button that I get the error. 

My first indication of trouble.......
ALL OF A SUDDEN one day the green level bar showed no signal.
I've been using wsjt-x for years with same hardware.

"so try a Windows restart"  .....was suggested...... yes I did a restart ....I did a zillion restarts while troubleshooting

Please note that ..................my radio is disconnected and OFF
Please note again that ........Rig = none
Please note again that ........FT-8 sample files decode flawlessly and repeatedly with clicking DECODE button

Please note again that ..     "Error in Sound Input" happens immediately when I click MONITOR button

Please note that .................I have been using this wsjt-x setup for 2 years with same hardware and connections.
Please note that............... .I have uninstalled and tries different wsjt-x versions many many many times

On 22/08/2021 06:19, bill333@... wrote:

Win10 | Elecraft K3 |  wired direct, K3 to Sound Card, No interface,

I've been used WSJT-X for 2 years, then suddenly it quit decoding from my K3, no GREEN signal bar or decode.  My WSJT-X is now as useful as a brick

Going to the most basic configuration.....
I disconnected all cables from my radio and decoded a sample .wav file, It worked OK
However.......When I hit MONITOR button I immediately get subject error (see subject line).
This happens with no cable connection to radio and with SETTINGS, RIG = none
I uninstalled and reinstalled Ver 2.4 several times and even want back to Ver 2.2..... same thing
I deleted all residual config and app-data files (that I could find) with WSJT name after I uninstalled.. still no help

In the past, during set-up, every time I turned on the radio I immediately got a green signal bar and things started decoding.
I've never had or seen the aforementioned error code and Ive been doing FT8 for years.
I tried many different settings with cables connected..... same problem.
I use an internal sound card, but purchased a new USB sound device and all new cables..... nothing gives me a GREEN signal bar.

Someone with internal knowledge of WSJT-X and the cause(s) of the aforementioned error would be of great assistance.  I did installed Ver 2.5-rc3, but backed off to Ver 2.4.  Possible I have screwed something up in the REGISTRY ?  HELP

Hi OM,

WSJT-X does not use the Windows registry.

The error message indicates you have not selected the correct audio devices in "Settings->Audio". Sometimes a pending Windows update can disrupt audio interfaces, so try a Windows restart (note not shutdown and reboot).

73
Bill
G4WJS.

 Win10 | Elecraft K3 |  wired direct, K3 to Sound Card, No interface,

I've been used WSJT-X for 2 years, then suddenly it quit decoding from my K3, no GREEN signal bar or decode.  My WSJT-X is now as useful as a brick

Going to the most basic configuration.....
I disconnected all cables from my radio and decoded a sample .wav file, It worked OK
However.......When I hit MONITOR button I immediately get subject error (see subject line).
This happens with no cable connection to radio and with SETTINGS,  RIG = none
I uninstalled and reinstalled Ver 2.4 several times and even want back to Ver 2.2..... same thing
I deleted all residual config and app-data files (that I could find) with WSJT name after I uninstalled.. still no help

In the past, during set-up, every time I turned on the radio I immediately got a green signal bar and things started decoding.
I've never had or seen the aforementioned error code and Ive been doing FT8 for years.
I tried many different settings with cables connected..... same problem.
I use an internal sound card, but purchased a new USB sound device and all new cables..... nothing gives me a GREEN signal bar.

Someone with internal knowledge of WSJT-X and the cause(s) of the aforementioned error would be of great assistance.  I did installed Ver 2.5-rc3, but backed off to Ver 2.4.  Possible I have screwed something up in the REGISTRY ?  HELP