The following system error occurred: Type mismatch.

[aleksandr]

Hello! when trying to update data via the web version, it writes an error: "The following system error occurred: Type mismatch. Unable to convert a value to the data type requested for table 'СправичникМесяца490' column 'ОтчетныйПериод'. The data provider was unable to convert the value 'ЯНВАРЬ 2014' from the source data type 'VT_BSTR' to the expected data type 'VT_DATE'. Please check the column data types in the data model and data source and ensure that the data types are compatible. The database operation was cancelled because of an earlier failure. Table: СправичникМесяца490"

Through the desktop version everything is ok. What could be the problem?

[v-juanli-msft]

Hi @aleksandr

This error could be an issue with your M script within your Power BI Desktop file.

Why refresh works in Power BI Desktop but not in Service, It may for the date conversions are handled differently in the Power BI Service, and the Power BI Service is not tolerant of an invalid date. 

As a temperary solution, you could refresh the PBIX in Desktop and re-upload the file to the Service.

Or you could check the column data types in the data model and data source and ensure that the data types are compatible. 

To explore about this error, please provide more details as below:

Which data format is the column 'ОтчетныйПериод'?

Please select this column, then Go to Modeling->Data type, format, show me the information or screenshot.

the value 'ЯНВАРЬ 2014' from the source data type 'VT_BSTR' to the expected data type 'VT_DATE'

do you ever change the value or data type of this value in your data source after importing to power bi?

could you show an example of data type 'VT_BSTR' in the source data and data type 'VT_DATE' in pbix?

Best reagrds

Maggie

[aleksandr]

Hello, Maggie! Data in the source table is stored in text format. In the model, I translate them into a date format. In the source table (MySQL) I can not change the source text format. Any idea how to get around this problem? (attached screenshots).

[aleksandr · Accepted solution]

I managed to solve the problem. I made a column [ОтчетныйПериод] format in the model as in the original column in the MySQL database. Then in the model created another column, the value of which is copied from the column [ОтчетныйПериод]. In the end, I assigned a date format to a new column and it worked. Maggie, thanks for responding.