ArcGIS Pro 3.6.1 CSV Join Issue

[EwaWdzieczak]

In ArcGIS Pro 3.6.1, attempting to use Add Join to join a feature class to a CSV table often results in incomplete, empty, or inconsistent joins. The tool completes without error, but expected joined fields either contain null values or fail to populate correctly, despite matching join keys.

This behavior is reproducible across multiple shapefiles and CSV tables and does not appear to be caused by field name or value mismatches. The same datasets successfully join when the CSV is converted to an Excel (.xlsx) file or when using the Join Field tool.

This behavior differs from earlier versions (e.g., ArcGIS Pro 3.4.4), where the same CSV joins functioned as expected. 

Was this a regression after 3.4.4?

[HaileyTimmons]

Check your field types, I usually have this issue if you are trying to join 2 different field types together. A Long field type needs to be joined to a Long field. I have this issue with Block Group ID's and have to convert them to the Big Integer Type, as that is how the excel sheet pulls in. If you right click the layer /csv, select data Design, Fields you can see the data type classification

[RichardDaniels]

Converting to Excel results in a well-defined field type for each column in the file. When using a csv the system guesses the field type based on a .ini file -or the first 20 rows in the CSV.

Also, if this is a large .csv ensure the file is NOT in the Cloud since you cannot guaranteed all the data to be accessible at all times on your local device (unless you explicitly checked that option in OneDrive for your file). This would explain why it appears to work but the expected records are not returned.