Deadlock error frequently

In de logging i find this error frequently, any idea why this happened?

RequiredFiles Deadlock when deleting required files - ignoring and continuing with request
RequiredFiles SQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction

What CMS and player versions are you using please?

This are my versions.
CMS: 1.8.6
Player: windows, 1.8.3, 130