No Micro SD Card Inserted but phone detects it I have an Android 4.0.4 Myphone A919 Duo.  I go to Settings > Storage.  Internal Storage: Total Space is 0.98 GB. Phone Storage: Total Space is 1.55 GB.  Then on SD CARD, it says Mount SD Card which is greyed out.

One of my apps, AppMgr III, shows an ON SD CARD tab with 1.55 GB of space.  The tab next to it is PHONE ONLY with 1005.93 MB of space.  I can tap on an app in the SD CARD tab and it gives the option to Move to Internal storage and the app launches and runs just fine with no errors.

I have another app, File Manager, that shows the directory /mnt/sdcard and a bunch of folders.

So basically with or without an SD card inserted, the Mount SD Card in Settings is greyed out and both apps are reporting an SD Card.  How can an app show an SD Card if there is no SD Card inserted and the Mount option is greyed out?  Does it have to do with cache?
That SDCARD is technically your internal storage mounted at /sdcard or /mnt/sdcard or even /storage/sdcard0. They aren't your external sdcard you can insert. That would be mounted to /external-sd/ or similar. The option is greyed out because there is no external sdcard to be mounted. So keep in mind that  there is a difference between sdcard (internal) and external sdcard. Just so you know: With the update to android 4.0 the internal and external sdcards have become a thing.