The hcnetsdk.dll 9 Hikvision error is a technical communication failure specifically defined as NET_DVR_NETWORK_RECV_ERROR. This code indicates that the Hikvision software (such as iVMS-4200) or a custom application using the SDK has successfully connected to a device but failed to receive data from it. Understanding Error Code 9

NET_DVR_NOERROR — but that indicates success, not an error.
Wait — actually, let me verify: In many Hikvision SDK versions, error code definitions vary.
However, from official Hikvision NET_DVR.h or davinci.h:

Missing Dependencies: The SDK may fail if Windows components like Visual C++ Redistributables or specific .NET versions are missing or corrupt. Summary Table: Hikvision HCNetSDK Error Codes

Network Config: Verify the Hikvision device has the correct DNS settings. Misconfigured DNS is a frequent cause of connection failures. 2. Fix Version and SDK Mismatches

NET_DVR_DEVICEINFO_V40 dev = 0; LONG userID = NET_DVR_Login_V40(&login, &dev); if (userID < 0) DWORD err = NET_DVR_GetLastError(); if (err == 9) printf("ERROR 9: Wrong password. Retry or reset device.\n");