OS: Windows 10 64bit build 19042.572
Convert image to HEIC/HEIF look succes (no errors or messages), but result in heic file is 0 bytes.
Effect: Saved file in HEIC/HEIF is 0 bytes.
To reproduce:
1. Open any PNG or JPG image (I've tested only them).
2. File - Save as (Ctrl + Shift + S).
3. Select HEIC - HEIF, save the image.
4. Status bar shows 0 bytes. Windows Explorer shows 0 bytes.
Actual behaviour (bug): Saved file in HEIC/HEIF is 0 bytes

Expected behaviour: Saved file in HEIC/HEIF is greater than 0 bytes and contains image.