What i mean is , often songs that re presently playing will randomly disappear from playing , i may be in my gym working out and suddenly music stops , i come out and there are no songs in JRiver .
If that is the way it happens, I would suspect you may have some corrupted or damaged audio files. Maybe. With that setting to keep the Playing Now list, it shouldn't be cleared when playback stops, for any reason really. There are some tools available that can check for corruption in audio files. An internet search should find some. I haven't had to use them, so don't know too much about them. MC usually tells me during Auto-Import if a song file is corrupted, in the detailed report at the end. But sometimes MC won't notice at Import time, as the files get corrupted later. Hence, tools to scan files and check them.
Where and how do i check for that driver ? And what do you mean by "are there sounds that...?"
The WDM driver is a sound input driver for MC, so that normal computer sounds or sounds from other applications are captured and played through MC, instead of using the Windows sound system. You can check if it is selected by right clicking on the speaker icon in the system tray (bottom right) of Windows, and then selecting "Playback Devices". This is outside MC of course. Windows will then show you all the available audio playback devices on your PC. One of them will be the "JRiver Media Center 22" device. If that is selected, you are using the WDM driver.
When you are using the WDM driver, normal computer sounds like receiving an email, Windows system notifications, or any sound that the PC makes when something happens on it, will be played through MC. That can be a problem sometimes, and may be stopping playback for you. But I'm not sure on that, and the Playlist shouldn't be cleared.