Hi,

It seems like you are writing to a path which is not empty and has some non - delta format files.

Also, can you confirm if the path mentioned in the error message "`s3://nbu-ml/projects/rca/msft/dsm09collectx/delta` " is the path you are writing to or reading from? I faced a similar error - but that was when I read a delta table path through : .option("cloudFiles.format", "parquet"). I overcame the error by adding spark.databricks.delta.formatCheck.enabled=false in spark config.