A: If you are using Android 11+ and updated to 2.19+ then it is not a bug.

Google forced to target Android 11 for all new updates going to Google Play. Due to that standard (classic) files access rights are removed from the app unless app requests All Files permission is prohibited for media apps by Google, so there is no possibility to revert to the old and very convenient for all behavior. There are two approaches to mitigate this problem:

  1. Delete existing source entries from the Sources section and create new which are using Google's new Scoped File Access (SAF) API which is the only possibility to access user files for the app. For that you need to: Sources -> [+] -> File System -> [+] -> select music folder in the OS selection dialog -> once confirmed by you this folder will be added to Neutron's File System list. After that you can tap on this entry to browse and select folders for scanning or you can select permitted folder directly and confirm scanning. Remember, SAF is 10 times slower than generic file access and it is cause by Google's bad implementation.
  2. Use Generic package from Neutron's web site which targets Android 8 and thus not restricted by Google. It will work exactly the same as pre 2.19 versions. You can download it here. If your device does not have Intel or AMD CPU then you will need ARM64 package. Turn off automatic updates for Neutron in  Google Play and when you see notification about available update in Google Play, Store update package from web site again. Install and keep enjoying Neutron!

Here is a SAF source creation flow:

1. Access Source Selection via Neutron's settings -> Media Library or Sources and use [+] to open Sources Selection. Tap on File System. 


2. If you are using 2.19+ version on Android 11+ then you won't see Device or SD, only access to Neutron's internal file system (sandbox) will be available. You can get access to it by activating the internal FTP server in Network settings. Tap on [+] in the bottom to add the permitted folder for Neutron's access.


3. OS will present dialog which allows to select folder and give permission for Neutron to access it, you can select either Internal Storage or SD by entering into the folder and pressing the Select button in the bottom.


4. For example, if you entered Music folder then in the bottom you have [Select] button which will add access permission for this folder to Neutron and you will see it added inside Neutron in Directory Selection dialog.

Note: for External SD you may want to select root of SD for greater compatibility and in case Neutron does not find any files during scanning.


5. Here is /Music folder in External SD was added to Neutron and you can either select it for scanning or tap and browse its sub-folders and select them for scanning.


6. Here while /Music folder is selected for scanning.