Problem setting monitor mode

[Grey-1]

Using Windows 10 Pro (version 22H2, Build 19045.5011), cannot set Monitor mode. Used a number of WiFi adapters including a Alfa AWUS1900. wlanhelper (running as administrator) reports that the adapter only supports managed mode.

Npcap 1.79 and updated drivers from Alfa.

[Grey-1]

Added note: I tried this on two different Windows systems.

[poeggi]

Same here, using an ASUS AC68 (which is also based on RTL8814AU chipset, like your Alfa)
Using NPCAP 1.80 and latest Wireshark 4.4.1

Asus drivers seem a bit dated, windows tells me they are from 2019:
"netrtwlanu.inf:a9e8526e3515713f:ASUS_RTL8814au.ndi.NT:1030.38.712.2019:USB\VID_0B05&PID_1853"
But I haven't found a newer version.

Wlanhelper errors out trying to set monitor mode (from an admin powershell):

PS C:\Windows\System32\Npcap> .\WlanHelper.exe "Wi-Fi 2" mode monitor
Error: SetWlanOperationMode::SetInterface error, error code = 50 (The request is not supported)
Failure

In fact it seems monitor mode is not supported:

PS C:\Windows\System32\Npcap> .\WlanHelper.exe "Wi-Fi 2" modes
managed

[QuestionQuest117]

I'm getting the same error with my AWUS036AXML. WlanHelper.exe outputs error code 50

[Aif4thah]

getting the same Error with npcap 1.80