MACIE not analyzing all files

With limited information I'll try to give you some possible causes/troubleshooting tips.

• Your .csv and .txt files may just not have any sensitive data. Here's the managed data identifiers Amazon Macie uses to detect PII. If the data in your .csv and/or .txt files don't match any of those identifiers, they won't show findings. You can always build your own custom identifiers if that's the case.
• The files may have a key pair associated with them that Amazon Macie doesn't have access to. If the files are encrypted, Macie needs access to the keys to scan for PII. Here's a link on setting that up should that be the case.
• Your Sampling Depth may not be 100%. If this value is less than 100%, Macie selects eligible objects to analyze at random, up to the specified percentage, and analyzes all the data in those objects. For example, if you configure a job to analyze 10,000 objects and you specify a sampling depth of 20%, the job analyzes approximately 2,000 randomly selected, eligible objects.
• The .csv and .txt files may have been added after the last scan. If it was a one time scan or if the files were added after the last scan, they may have not picked up yet.

These are just a few of the steps you can take to troubleshoot the issue. Of course if these don't work please open a case with Amazon Support and they will be able to get you squared away.