many custom shapes/white boxes

hello
I have read about the issue being brought up a few times. How do i delete all of the custom shapes from the top of my Office Calc files in version 6.4.2.2. my files were originally MS Office files. If i try to delete them while navigator is open i can see that as I delete one it automatically comes back. Also if i go to tools/options/LibreOffice Calc/View and hide the drawing opjects they disappear but back in the spreadsheet I can not select the drop down filter boxes at the top of the spreadsheet. I have also tried starting in safe mode but they are still there in safe mode. It pretty much makes my files useless as I cant use the filter boxes at the top of the file. I have also just found that if i open the exact same file from an external hard drive the problem does not exist, but it exists on the file in my laptop. Please help