Alter field failing

[YusefSamari]

I am trying to alter the name of a 'Double' field using the Alter Field tool in Pro 3.1.3. 

I am getting the error message 001600 Failed to alter field name:

I cannot figure out why. Here is the settings on the tool:

There is no option for field length coming up, but the field I am trying to change is null for all values except for one, which has a value '1'. So it doesn't seem to be an issue with a mismatch in field length. Other than that, I'm stumped!

Any help much appreciated, thanks.

[AngelaSchirck]

Is the field marked "is required" or "read only"?

[YusefSamari]

No, it is not:

Thanks for your reply though! Any other ideas?

[AngelaSchirck]

Does your original field have an alias? This could be the problem.  Since your alias is the same as your field name why don't you try leaving it blank and checking the "clear alias" box.  I don't know what's causing the issue, but it's worth a try.  But I still think that error number corresponds to a restricted field somehow. 

Another option, since you say all the records are empty in that field except one, why don't you just create a new field, and delete that one?

[YusefSamari]

Thanks. The original field didn't have an alias. I have tried leaving the alias blank and ticking the 'clear alias' box, but get the same error. One thing that might be worth mentioning is that the field I am trying to alter was joined from another table using the Join Field tool. Would that influence things? 

I have tried calculating a new field based on this one I am trying to alter, then deleting the new field. That works. I am trying to incorporate this into a model though, where I am joining this field to another several times, with a different selection in place each time. There would be less steps involved using Alter Field rather than Calculate Field then Delete Field. In any case, I would like to know what is going on just for the sake of my own understanding! Thanks for your help so far.

[AngelaSchirck]

You might need to alter the field first then join the tables, that could be the problem.  Other than that, I'm out of ideas 🙂

[YusefSamari]

Thanks. I will give that a go.

[Robert_LeClair]

Interesting - so in the Alter Field GP tool help page it mentions that the New Field Type (optional parameter) "Specifies the new field type for the field. This parameter is only applicable if the input table is empty (does not contain records)."  Clearly your table does contain records.  Try this - leave the New Field Type parameter blank and run the tool again.  What is the output?