Not picking up VOB files.

I have an andriod tablet and can’t transfer vob files onto the micro SD card. 

I selected the folder in which the VOB file was contained in. It didn’t show up.

Does that mean I need to convert it? If so, how do I do that? and what file should I convert it into?

Thanks in advance.

It could be. Can you copy files in other formats aside from VOB?

If you have another micro SD, better try that one too. 

How big are your VOB files?  If they are larger than 4GB you can’t write them to the card unless you reformat the card to an NTFS format which may or may not be compatible with your Android.  The standard format for removable devices is FAT32 which is compatible with just about everything but has a file size limitation of 4GB.