Unable to replace blank fields using Find and Replace in ArcGIS Pro

Description

When attempting to replace blank fields with new values using the Find and Replace tool, no results are returned, and no replacements are made.

Cause

There is a space in the fields. One or more spaces in a field is considered a value. Therefore, the Find and Replace tool is unable to replace the fields with new values.

The image below of the ReliefStatus attribute table displays spaces in a field, also called ReliefStatus, by the cursor location when individual cells are selected.

Solution or Workaround

Remove spaces using the Calculate Field tool

1. In the ArcGIS Pro Content pane, right-click the feature layer and select Attribute Table to open the layer's attribute table.
2. In the attribute table, right-click the field and click Calculate Field. A field named 'ReliefStatus' is used in this example.
3. In the Calculate Field window, configure the parameters.
   1. For Input Table, ensure the layer selected in Step 1 is prefilled. The input table is ReliefStatus.
   2. For Field Name (Existing or New), ensure the selected field name is prefilled. Otherwise, select the ReliefStatus field from the drop-down menu.
   3. For Expression Type, select Python.
   4. For Expression, in the expression box, type the code provided below. Replace <FieldName> with the name of the field with single spaces to be removed. In this example, the single space in the ReliefStatus field is removed.

!<FieldName>!.replace(" ","")

1. 5. Click OK.

Note: 
The Calculate Field tool permanently modifies inputs by changing values in the fields. To avoid undesired data changes, toggle Enable Undo on in the Calculate Field window before running the tool.

The attribute table below shows that spaces are removed from the field.

Use the Find and Replace tool

Alternatively, insert a single space in the Find box and the intended new value in the Replace box using the Find and Replace control. Refer to ArcGIS Pro: Replace values in a table cell for instructions.