Does the import wizard have any limits?

The import wizard is the best way to add and update records in Campaign Monitor.  But there are some limitations worth noting:

If you are using Salesforce reports then you will be limited to 50,000 records. This is the same limit you will run into if you attempt to add more than 50,000 records to a Salesforce campaign. In practice, this limit can generally be easily worked around.

• Consider adding more filters to reduce the records in the report.  For example, if you are scheduling the import then it is likely that records will not have changed since the previous import.  You could filter your report to only include recently modified records.
• Making reports as efficient as possible also helps when the import wizard runs.  We recommend using a tabular format, only including the columns you need to map. Do not include groupings or totals.
• If your import is quite basic and you are not using Salesforce Professional Edition you can use a list view.
• Or if you know how SOQL works you can use this as an import source.
• You could export the Salesforce report to CSV and directly import it into Campaign Monitor (i.e., outside of Salesforce). After that initial import, you can filter your Salesforce report to only includes records that have been modified in the last 24 hours. Finally, you can then use the import wizard with the amended report.
  

Salesforce reports can become corrupted, itis rare. This is not easy to spot within Salesforce. So if you are happy with the points above, the import is not working, then consider creating a new report from scratch.

If you working within a Salesforce Professional Edition org you will not be able to use list views. Again this is a limitation of how the Salesforce platform works. The best option is usually to use a Salesforce report instead.

The import wizard has in-built error reporting so when it runs, and if a problem is encountered there should be a reason shown. You can also check our maintenance logs within the Campaign Monitor Admin app in Salesforce.