diff --git a/1.sources/MyHealth/docroot/profile/RegisterUser.xhtml b/1.sources/MyHealth/docroot/profile/RegisterUser.xhtml
index 6423bc1..1882f3e 100644
--- a/1.sources/MyHealth/docroot/profile/RegisterUser.xhtml
+++ b/1.sources/MyHealth/docroot/profile/RegisterUser.xhtml
@@ -66,13 +66,15 @@
 						</div>
 						<div class="ui-g-4 ui-md-4">
 							<div class="ui-inputgroup">
-								<p:inputText id="nif" widgetVar="nif" value="#{RegisterUser.nif}" validator="nifValidator" maxlength="20" required="true" requiredMessage="Por favor, indque su NIF">
+								<p:inputText id="nif" widgetVar="nif" value="#{RegisterUser.nif}" validator="nifValidator" binding="#{nif}" maxlength="20" required="true"
+									requiredMessage="Por favor, indque su NIF">
 									<f:validator validatorId="nifValidator" for="nif">
 										<f:attribute name="managedBean" value="#{RegisterUser}" />
 									</f:validator>
-									<p:ajax event="change" update="nifmsg" oncomplete="handleNIFResponse(xhr, status, args)" />
+									<p:ajax event="change" update="nifmsg,nifButton" />
 								</p:inputText>
-								<p:commandButton id="nifButton" widgetVar="nifButton" onclick="nifCheckClick();" icon="pi pi-check" styleClass="green-button" />
+								<p:commandButton id="nifButton" widgetVar="nifButton" onclick="nifCheckClick();" icon="pi #{nif.valid ? 'pi-check' : 'pi-times'}"
+									styleClass="#{nif.valid ? 'green-button' : 'red-button'}" />
 							</div>
 						</div>
 						<div class="ui-g-6 ui-md-6">
diff --git a/1.sources/MyHealth/docroot/profile/UpdateProfile.xhtml b/1.sources/MyHealth/docroot/profile/UpdateProfile.xhtml
index 095f009..2dedab5 100644
--- a/1.sources/MyHealth/docroot/profile/UpdateProfile.xhtml
+++ b/1.sources/MyHealth/docroot/profile/UpdateProfile.xhtml
@@ -45,9 +45,10 @@
 								<f:validator validatorId="nifValidator" for="nif">
 									<f:attribute name="managedBean" value="#{UpdateProfile}" />
 								</f:validator>
-								<p:ajax event="change" update="nifmsg" oncomplete="handleNIFResponse(xhr, status, args)" />
+								<p:ajax event="change" update="nifmsg,nifButton" />
 							</p:inputText>
-							<p:commandButton id="nifButton" widgetVar="nifButton" onclick="nifCheckClick();" icon="pi pi-check" styleClass="green-button" />
+							<p:commandButton id="nifButton" widgetVar="nifButton" onclick="nifCheckClick();" icon="pi #{nif.valid ? 'pi-check' : 'pi-times'}"
+								styleClass="#{nif.valid ? 'green-button' : 'red-button'}" />
 						</div>
 					</div>
 					<div class="ui-g-6 ui-md-6">
diff --git a/1.sources/MyHealth/docroot/resources/js/common.js b/1.sources/MyHealth/docroot/resources/js/common.js
index f65c742..1b4a19d 100644
--- a/1.sources/MyHealth/docroot/resources/js/common.js
+++ b/1.sources/MyHealth/docroot/resources/js/common.js
@@ -30,6 +30,7 @@ function nifCheckClick() {
 // Actualiza la interfaz tras validar si un nif está duplicado.
 function handleNIFResponse(xhr, status, args) {
 	var isValid = false;
+	return;
 	
 	if (typeof args.validationFailed != "undefined")
 		isValid = !args.validationFailed;
diff --git a/1.sources/MyHealth/src/managedbean/validators/NifValidator.java b/1.sources/MyHealth/src/managedbean/validators/NifValidator.java
index 95e48c0..25bd686 100644
--- a/1.sources/MyHealth/src/managedbean/validators/NifValidator.java
+++ b/1.sources/MyHealth/src/managedbean/validators/NifValidator.java
@@ -48,7 +48,7 @@ public class NifValidator implements Validator<String>, ClientValidator {
 
 		if (nifIsDupe == true)
 			throw new ValidatorException(
-					new FacesMessage(FacesMessage.SEVERITY_ERROR, "El NIF está duplicado", "El NIF " + strValue + " pertenece a otro usuario previamente registrado"));
+					new FacesMessage(FacesMessage.SEVERITY_WARN, "El NIF está duplicado", "El NIF " + strValue + " pertenece a otro usuario previamente registrado"));
 
 		PrimeFaces.current().ajax().addCallbackParam("NIFisValid", true);
 	}