I have just installed solidworks 2016 ans while opening older files (solidworks 2013), I have issues with the screws, they're not right, they appear gigantic
Welcome to the forum. I assume those are Toolbox parts? See if #5 at Frequently Asked Forum Questions will help.
I had the same problem. We don't use Toolbox for our hardware, but our own database. Not all the hardware came in large, so I couldn't figure it out either until I went to File Locations and unchecked the box as discussed in #5 at Frequently Asked Forum Questions. Fixed the problem right away.
You still have the 2013 toolbox on your PC, and 2016 toolbox was installed. Change your file location of the toolbox to look at the old one.
I also don't use toolbox because of this problem. For multiple users, have everyone point to one shared toolbox on a server.
2016 was installed on a new machine for me, so there was no other toolbox installed for it to cause this problem. I just unchecked the box and have no problems now since we don't use it at all.
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