Governance problems within Spreadsheets.
According to schematiq.com 90% of spreadsheets with over 150 rows can contain severe problems, which can conclude in major financial losses.
There are many problems found in spreadsheets, for example when a good spreadsheet is changed it can be prone to major risk and error. Here are some website links that suggest how to solve a few common errors:
http://www.schematiq.com/excel-schematiq
http://www.alphr.com/business/1000859/7-spreadsheet-problems-and-how-to-solve-them