Cannot Create Report or Dashboard Folder in Lightning Experience

This issue occurs because the Unique Folder Name field in Salesforce Lightning Experience only accepts alphanumeric characters and underscores. Unlike Salesforce Classic, Lightning Experience does not display the specific validation error, making the cause unclear to the user.

Symptom:

The following error message appears when attempting to create a Report or Dashboard folder in Lightning Experience:

"The folder named (folder name) could not be created."

In Salesforce Classic, the error displayed is "Invalid Data," but Lightning Experience does not show the specific reason for the error.

Resolution Steps:

In the folder creation screen, locate the Unique Folder Name field.

Ensure the field contains only alphanumeric characters (A–Z, a–z, 0–9) and underscores (_).

Remove unsupported characters such as:

Spaces

Hyphens (-)

Double-byte characters (for example, Japanese characters such as 「あ」)

Other symbols

Re-enter a valid Unique Folder Name and click Save.