UsersWP keeps each custom account field in its own column of the uwp_usermeta database table. When you save a field in UsersWP > Form Builder, UsersWP changes that column with an ALTER TABLE query. “Column change failed, you may have too many columns” means the database refused that change. Until it is fixed, the field settings do not save, and users’ entries in that field may not save either.

Common causes

• The table is at the MySQL row size limit. Every text field adds a column, and MySQL caps how much a row can hold, so sites with many fields can hit it.
• The column for the field no longer exists, for example after a migration or a partial database restore, so there is nothing to change.
• The database user lacks permission to alter tables. Some hosts restrict this.
• The default value does not fit the field type, for example text in a number field.

Fix it

1. Back up the database first.
2. Export your users from UsersWP > Import/Export > Users so you have a copy of the field data.
3. Remove fields you no longer use from the account form. Each one you delete frees a column.
4. For the field that fails, delete it and add it again with the same field key.
5. Import the user data back from the export if you need to.

Deleting a field from the account form drops its database column, and with it every value users entered in that field. If a field is used by more than one registration form, the column is kept until it is removed from all of them.

If new fields cannot be created either (“Column creation failed”), the table is most likely full. Fewer fields, or switching long text fields to fewer, combined fields, is the lasting fix. Your host can also tell you whether the database user has ALTER privileges.