Hi Ranwo and welcome to the community Forum 
Have you installed a SD memory card and if so, how is it formatted (internal or external / portable)?
It is strongly recommended NOT to format SD cards as internal memory, even if the temptation is strong. There have been many problems. If this is your case, do not remove the card straight away, as this would be like ripping out built-in memory. Instead you’ll need to “evacuate” it (move everything that’s on it back to internal built-in memory) before physically removing it. [Edit - see this:
Even if formatted as external / portable memory, SD cards can be the cause of problems of all sorts. Have a look round.
Make sure your data are backed up before taking action.