Type change not allowed error while changing the type of a field which has data in it

[Nagashree5]

Hi All,

I'm getting the below error when tried to change a field type from Single line text to Reference. This field is on a custom table.

Type change not allowed. Invalid type conversion for field 'Entity Name' on table 'IT Incident'. Cannot convert from 'String' to 'Reference'. There exist data records (100) that are not a Sys ID.

 Has anyone faced this issue? can some please help to resolve issue.

TIA

[Amit Verma]

Hi @Nagashree5 

Refer below posts and try to resolve your issue :

https://www.servicenow.com/community/itsm-forum/error-in-update-set-quot-type-change-not-allowed-quo...

https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB0695947

Thanks & Regards

Amit Verma

[Dr Atul G- LNG]

Hi @Nagashree5 

The reason is bcz the pre build data is string format and now you are coverting it to Reference,

You can do 

- Take backup of this data.

- Clear all the values 

-Change the data type

- Upload the back up data.

[Nagashree5]

Hi @Dr Atul G- LNG,

We have 600 records atm with the values, Can you please guide how to exactly update the records after deleting the values.

TIA.

[Dr Atul G- LNG]

Hi @Nagashree5 

Try this in PDI first.

Create the dummy data.

Download the same in excel

change the data type to refence

Uploads data. make sure the field value must be in Reference.