By Nicholas Bowley, IMAGINiT Building Solutions
Check to see which Service Pack you are using by clicking the down arrow at the top right corner of your screen and then click “About Autodesk AutoCAD 2015” and see if it says “Service Pack 2”. If it does, this Hotfix may help you.
Autodesk put out a hotfix to resolve an issue related to Service Pack 2. The problem does not present itself in all files, just some which may contain certain fonts.
Autodesk® AutoCAD® 2015 Big Font Hotfix Follow this link to the hotfix:
Be sure to look at the readme file for instructions. You will need to find and replace the acdb20.dll file. Back-up the original file just in case you need to restore it.