I'm using the latest version of MusicBee on Microsoft Store, Windows 10 Build 1803
The SD card I'm using is a Samsung EVO Plus MicroSD 256GB (UHS-I) pluging in a Sony Xperia XA1 Plus running Android 8.0 as an MTP device
1. The first time I use that MTP sync feature in MusicBee, I tried to sync all of my library which is about 150GB to my SD card and it failed, it said my SD card is out of space. When I check, it is out of space but the sync process was not even done, and when I checked, the size all folders in the SD card was not even enough to take up over 100GB, no file or folder was hidden so I didn't know what was taking up that much space, I had to format it and copy my music library manually via Windows Explorer
2. This time, I tried to sync only 1 1.34GB album, I deleted it on my SD card right before syncing for this test, the sync preview give me no result for some reason so I right-clicked on the album and sent that album to my device. But it failed and it said "The system cannot find the path specified", and when I checked the storage of all the folders in the SD card, the used space of all folders and the SD card and are different again. The 3rd and 4th time I tried to send files via MusicBee, it still failed but no more space was taken.
The screenshots about size differences and my sync settings: https://imgur.com/a/KlTc6S3
Please give me an idea how can I fix the storage on my SD card without formatting it again. And I made sure that no file or folder is hidden. The used space is the same when I checked on my phone.