Please post a logfile from a live streaming or recording session at least 30 seconds in length, where the problem was occurring (so with a Window Capture present and pointed at a window, but with nothing being captured). We can take a look at what's happening on the back-end that could be causing this.
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Thank you for your help..see below for my log file where I attempted to add a scene, then add window capture as a source.
11:03:04.128: CPU Name: Intel(R) Core(TM) i5-7200U CPU @ 2.50GHz
11:03:04.128: CPU Speed: 2712MHz
11:03:04.128: Physical Cores: 2, Logical Cores: 4
11:03:04.128: Physical Memory: 8060MB Total, 5584MB Free
11:03:04.128: Windows Version: 10.0 Build 18363 (release: 1909; revision: 1316; 64-bit)
11:03:04.128: Running as administrator: false
11:03:04.128: Aero is Enabled (Aero is always on for windows 8 and above)
11:03:04.128: Windows 10 Gaming Features:
11:03:04.128: Game DVR: On
11:03:04.131: Sec. Software Status:
11:03:04.132: Windows Defender Antivirus: enabled (AV)
11:03:04.133: Windows Firewall: enabled (FW)
11:03:04.133: Current Date/Time: 2021-01-28, 11:03:04
11:03:04.133: Browser Hardware Acceleration: true
11:03:04.133: Portable mode: false
11:03:04.664: OBS 26.1.1 (64-bit, windows)
11:03:04.664: ---------------------------------
11:03:04.686: ---------------------------------
11:03:04.686: audio settings reset:
11:03:04.686: samples per sec: 48000
11:03:04.686: speakers: 2
11:03:04.687: ---------------------------------
11:03:04.687: Initializing D3D11...
11:03:04.687: Available Video Adapters:
11:03:04.690: Adapter 0: Intel(R) HD Graphics 620
11:03:04.690: Dedicated VRAM: 134217728
11:03:04.690: Shared VRAM: 4225880064
11:03:04.690: PCI ID: 8086:5916
11:03:04.690: Driver Version: 25.20.100.6446
11:03:04.690: output 0: pos={0, 0}, size={1920, 1080}, attached=true, refresh=60, name=
11:03:04.692: Loading up D3D11 on adapter Intel(R) HD Graphics 620 (0)
11:03:04.713: D3D11 loaded successfully, feature level used: b000
11:03:04.713: DXGI increase maximum frame latency success
11:03:05.286: ---------------------------------
11:03:05.286: video settings reset:
11:03:05.286: base resolution: 1920x1080
11:03:05.286: output resolution: 1280x720
11:03:05.286: downscale filter: Bicubic
11:03:05.286: fps: 30/1
11:03:05.286: format: NV12
11:03:05.286: YUV mode: 709/Partial
11:03:05.286: NV12 texture support not available
11:03:05.286: Audio monitoring device:
11:03:05.286: name: Default
11:03:05.286: id: default
11:03:05.289: ---------------------------------
11:03:05.298: [CoreAudio encoder]: CoreAudio AAC encoder not installed on the system or couldn't be loaded
11:03:05.299: Failed to load 'en-US' text for module: 'decklink-captions.dll'
11:03:05.304: Failed to load 'en-US' text for module: 'decklink-ouput-ui.dll'
11:03:05.352: [AMF] Unable to load 'amfrt64.dll', error code 126.
11:03:05.354: [AMF] AMF Test failed due to one or more errors.
11:03:05.354: Failed to initialize module 'enc-amf.dll'
11:03:05.503: [obs-browser]: Version 2.9.1
11:03:05.503: [obs-browser]: CEF Version 75.1.16+g16a67c4+chromium-75.0.3770.100
11:03:05.600: VLC found, VLC video source enabled
11:03:05.619: A DeckLink iterator could not be created. The DeckLink drivers may not be installed
11:03:05.620: No blackmagic support
11:03:05.639: ---------------------------------
11:03:05.640: Loaded Modules:
11:03:05.640: win-wasapi.dll
11:03:05.640: win-mf.dll
11:03:05.640: win-dshow.dll
11:03:05.640: win-decklink.dll
11:03:05.640: win-capture.dll
11:03:05.640: vlc-video.dll
11:03:05.640: text-freetype2.dll
11:03:05.640: rtmp-services.dll
11:03:05.640: obs-x264.dll
11:03:05.640: obs-vst.dll
11:03:05.640: obs-transitions.dll
11:03:05.640: obs-text.dll
11:03:05.640: obs-qsv11.dll
11:03:05.640: obs-outputs.dll
11:03:05.640: obs-filters.dll
11:03:05.640: obs-ffmpeg.dll
11:03:05.640: obs-browser.dll
11:03:05.640: image-source.dll
11:03:05.640: frontend-tools.dll
11:03:05.640: enc-amf.dll
11:03:05.640: decklink-ouput-ui.dll
11:03:05.640: decklink-captions.dll
11:03:05.640: coreaudio-encoder.dll
11:03:05.640: ---------------------------------
11:03:05.640: ==== Startup complete ===============================================
11:03:05.685: All scene data cleared
11:03:05.685: ------------------------------------------------
11:03:05.990: WASAPI: Device 'Speakers (Realtek High Definition Audio)' [48000 Hz] initialized
11:03:05.995: [Loaded global audio device]: 'Desktop Audio'
11:03:06.063: WASAPI: Device 'Microphone (Realtek High Definition Audio)' [48000 Hz] initialized
11:03:06.063: [Loaded global audio device]: 'Mic/Aux'
11:03:06.069: [duplicator-monitor-capture: 'Display Capture'] update settings:
11:03:06.069: display: 1 (1920x1080)
11:03:06.069: cursor: true
11:03:06.071: Switched to scene 'Scene'
11:03:06.072: ------------------------------------------------
11:03:06.072: Loaded scenes:
11:03:06.072: - scene 'Scene':
11:03:06.072: - source: 'Display Capture' (monitor_capture)
11:03:06.072: - source: 'Window Capture 2' (window_capture)
11:03:06.072: - scene 'Timer':
11:03:06.072: - source: 'Window Capture' (window_capture)
11:03:06.072: ------------------------------------------------
11:03:06.091: adding 21 milliseconds of audio buffering, total audio buffering is now 21 milliseconds (source: Mic/Aux)
11:03:06.091:
11:03:11.964: User Removed source 'Display Capture' (monitor_capture) from scene 'Scene'
11:03:15.213: User Removed source 'Window Capture 2' (window_capture) from scene 'Scene'
11:03:15.973: User switched to scene 'Timer'
11:03:18.309: User switched to scene 'Scene'
11:03:18.309: User Removed scene 'Timer'
11:03:26.043: [duplicator-monitor-capture: 'Display Capture'] update settings:
11:03:26.043: display: 1 (1920x1080)
11:03:26.043: cursor: true
11:03:26.047: User added source 'Display Capture' (monitor_capture) to scene 'Scene'
11:03:36.777: User added scene 'Window'
11:03:36.778: User switched to scene 'Window'
11:03:41.192: User added source 'Window Capture' (window_capture) to scene 'Window'
11:03:58.966: User switched to scene 'Scene'
11:03:58.975: User Removed scene 'Window'
11:04:01.063: >>> nv12 tex not active, fall back to old qsv encoder
11:04:01.063: [qsv encoder: 'simple_h264_stream'] settings:
11:04:01.063: rate_control: CBR
11:04:01.063: target_bitrate: 2500
11:04:01.063: fps_num: 30
11:04:01.063: fps_den: 1
11:04:01.063: width: 1280
11:04:01.063: height: 720
11:04:01.063: [qsv encoder: 'simple_h264_stream'] debug info:
11:04:01.074: impl: D3D11
11:04:01.074: surf: D3D11
11:04:01.217: m_nSurfNum: 12
11:04:01.227: m_nTaskPool: 4
11:04:01.227: major: 1
11:04:01.227: minor: 27
11:04:01.227: ---------------------------------
11:04:01.227: [FFmpeg aac encoder: 'simple_aac'] bitrate: 160, channels: 2, channel_layout: 3
11:04:01.227:
11:04:01.245: ==== Recording Start ===============================================
11:04:01.245: [ffmpeg muxer: 'simple_file_output'] Writing file 'C:/Users/steve/Videos/2021-01-28 11-04-01.mp4'...
11:04:09.772: User added scene 'window'
11:04:09.773: User switched to scene 'window'
11:04:14.778: User added source 'Window Capture' (window_capture) to scene 'window'
11:04:36.440: [ffmpeg muxer: 'simple_file_output'] Output of file 'C:/Users/steve/Videos/2021-01-28 11-04-01.mp4' stopped
11:04:36.440: Output 'simple_file_output': stopping
11:04:36.440: Output 'simple_file_output': Total frames output: 1045
11:04:36.440: Output 'simple_file_output': Total drawn frames: 1056
11:04:36.441: ==== Recording Stop ================================================
