The FL Studio trial installer page show the installer file size in bytes so that you can check that the complete installer file has downloaded.
Please note that Windows can indicate a difference in size between size in Mb (Mega bytes) and size in bytes.
Because:
1 megabyte (MB) = 1,048,576 bytes. The confusion occurs because a the multiplier from kilobyte (KB) to MB = 1024 NOT 1000 as you may expect. Further a KB = 1024 bytes. So a MB = 1024 bytes * 1024 = 1,048,576 bytes = 1 MB.
If you multiply this 'hidden' 48,576 bytes for each MB of the download file, you will see where the size difference in MB and bytes comes from.
You can view the installer size in bytes from the Window's file 'properties':
Right click the file in Windows Explorer (or in My Computer) and select properties from the menu.
On the 'General' tab you will see the file size in Mb and bytes, the byte value it is hopefully the same as indicated on the download page. If it isn't select another download location and re-download it.
The FL Studio Support Team.