How to see internal as well as external storage of an Android 9 phone during File Transfer?

[Android Central Question]

I purchase an Umidigi F1 Play phone (Android 9) recently and inserted my 128 GB micro-SD card in there. If used as external storage I see both storages: "Internal shared storage" 50 GB free of 52,3 GB and "SanDisk SD Card" 119 GB free of 119 GB, when connected to a Windows PC with File Transfer option.
But if I format the micro-SD card to internal storage I see either (1) the internal storage only if I chose the option to "to move data later" during the formatting process or (2) the external storage only if I chose to "move data now" during the formatting process. On windows it says "Internal shared storage" though, despite showing only the 115 GB belonging to the micro-SD card.
I also tried rebooting the phone multiple times without the problem being solved.

So my question is, whether there is a way to see both storages when the micros-SD card is used as internal storage with Android 9? (I know I had that option on my old phone with Android 8.1.0)

 

[methodman89]

Try Data Size Explorer from the play store

 

[fdx3]

I'm the OP.
To clarify: when the microSD card is formatted and used as internal storage, only it's capacity will be shown in various file managers (from google play store) and on a Windows running PC, but not the free ~54 GB of the real internal memory.

If no one knows a fix, I'd at least want to know, whether it's an Android 9 problem or one of Umidigi F1 Play phones.

 

[joeldf]

That's how "adoptable" storage works. When formatted as internal storage, both on-board memory and the SD card become one shared memory space for the device to use. They are no longer considered separate spaces.

Great for low memory devices that get filled up with apps after only installing a few, but a terrible idea if you already have plenty and just need file/image storage space. Now, if the card craps out, or if you remove the card before proper preparation, you've screwed up the whole device.

 

[Mooncatt]

Welcome to the forums!
@joeldf is correct, but it should also be noted that not every manufacturer implements adoptable storage correctly, leading to these types of issues. That, and the performance tradeoffs/risks, are why adoptable storage isn't really a recommended practice. You're better off leaving it formatted as external storage, and keeping apps on internal storage. The sd card is best for stand alone file types, like documents and media.

 

[fdx3]

Thank you joeldf.
Your post made me recheck with my old Android 8.1.0 phone. And indeed, it looks like I could only see the external disc's capacity in the file manager and on my PC all along, when it was formatted/used as internal... At least it wasn't a problem with my new phone's model.