Dear Allhope you all are well.I am facing a problem of drawing size. I am working on interior detail drawing. My working drawing size in 9MB, When I remove everything from the drawing and purge it all and then save it to my computer, the drawing size should be reduce but the drawing size is remain as before purge. Even when I am starting a new drawing and saving it without draw any thing, the drawing size is 4.5MB.What should I do for saving it in actual size?I will be very thankful to you.

Is there any evidence of .DGN linetypes or text being loaded?

There are some custom hatch patterns loaded, also some useless textstyles & line types are loaded as you can see in attach image. I don't know where its(linetypes & tex styles) comes from. also dont know how to delete or remove it.

1- start from new dwg.2-use dwg-purge external command (download & install first)3-saveas as dwt format acad.dwt / any name.4- close.5- start new dwg with the last created dwt file. I hope it will solve your issue. 
aqeel2222019-12-19 14:16:48

ISSUE IS NOT RESOLVED YET 

Can you upload the file so we can have a look?

YES

NOT UPLOADING DUE TO LRGE FILE SIZE.

If you guys don't mind so we can talk on whatsapp  . May be the issue can resolve on whatsapp by doing clear chat.+923042210396

If all you require is a clean acad.dwt (or acadiso.dwt) delete what is being used by AutoCAD now and rename the backup version which is in the same directory.