I am new to using CIVI at my work place, and there are a ton of duplicate entries in the system (we did a merge from our previous system). Is there a quick and easy way to merge all duplicate contacts?
Yes. One of the questions to consider is what you mean by a duplicate. If two contacts have the same first and last names, same address, same email and same date of birth, then you're fairly safe in assuming they represent the same person. But real data is far messier and incomplete so Civi lets you choose what characteristics to look for - those are described by a 'Dedupe Rule'.
If you have lots of duplicates you will need to repeat the process several times using different dedupe rules. I tend to start with quite specific ones (eg first name, last name, postcode), deal with those, then broaden the criteria.
- go to
Contacts > Find and Merge Duplicate Contacts
Use Ruleon one of the Individual Rules, or
Add Rule for Individualsto set up a new rule
- select a group - or leave it blank to search all contacts
- review the duplicates and merge them
For much more detail, see https://docs.civicrm.org/user/en/stable/common-workflows/deduping-and-merging/
In addition to Aidan's answer, CiviCRM does come with a Batch Merge tool which can resolve the most straightforward of matches and leave you to just deal with the odd or complex ones manually.
This process is described in the section "Merging multiple contacts simultaneously" in https://docs.civicrm.org/user/en/4.7/common-workflows/deduping-and-merging/