diff --git a/core/cmdbchangeop.class.inc.php b/core/cmdbchangeop.class.inc.php
index ae1f6a154c..c87d6c739e 100644
--- a/core/cmdbchangeop.class.inc.php
+++ b/core/cmdbchangeop.class.inc.php
@@ -175,22 +175,12 @@ class CMDBChangeOpDelete extends CMDBChangeOp
 	}
 }
 
-/**
- * Interface iCMDBChangeOpSetAttribute
- *
- * @since 2.8.0
- */
-interface iCMDBChangeOpSetAttribute
-{
-
-}
-
 /**
  * Record the modification of an attribute (abstract)
  *
  * @package     iTopORM
  */
-class CMDBChangeOpSetAttribute extends CMDBChangeOp implements iCMDBChangeOpSetAttribute
+class CMDBChangeOpSetAttribute extends CMDBChangeOp
 {
 	/**
 	 * @inheritDoc
diff --git a/core/userrights.class.inc.php b/core/userrights.class.inc.php
index 283f6cc688..5757ec353d 100644
--- a/core/userrights.class.inc.php
+++ b/core/userrights.class.inc.php
@@ -1291,7 +1291,20 @@ class UserRights
 		}
 		if (is_null($oUser))
 		{
-			return '';
+			$sInitials = '';
+			$aLoginParts = explode(' ', $sLogin);
+			foreach($aLoginParts as $sLoginPart)
+			{
+				// Keep only upper case first letters
+				// eg. "My first name My last name" => "MM"
+				// eg. "Carrie Anne Moss" => "CAM"
+				if(preg_match('/^\p{Lu}/u', $sLoginPart) > 0)
+				{
+					$sInitials .= mb_substr($sLoginPart, 0, 1);
+				}
+			}
+
+			return $sInitials;
 		}
 		return $oUser->GetInitials();
 	}
diff --git a/sources/application/UI/Layout/ActivityPanel/ActivityEntry/ActivityEntry.php b/sources/application/UI/Layout/ActivityPanel/ActivityEntry/ActivityEntry.php
index b342fc204c..d12ca2eca7 100644
--- a/sources/application/UI/Layout/ActivityPanel/ActivityEntry/ActivityEntry.php
+++ b/sources/application/UI/Layout/ActivityPanel/ActivityEntry/ActivityEntry.php
@@ -51,7 +51,7 @@ class ActivityEntry extends UIBlock
 	protected $sType;
 	/** @var string $sDecorationClasses CSS classes to use to decorate the entry */
 	protected $sDecorationClasses;
-	/** @var string $sContent Raw content of the entry itself (should not have been processed / escaped) */
+	/** @var string|null $sContent Raw content of the entry itself (should not have been processed / escaped) */
 	protected $sContent;
 	/** @var \DateTime $oDateTime Date / time the entry occurred */
 	protected $oDateTime;
@@ -72,7 +72,7 @@ class ActivityEntry extends UIBlock
 	 * ActivityEntry constructor.
 	 *
 	 * @param \DateTime $oDateTime
-	 * @param \User $sAuthorLogin
+	 * @param string $sAuthorLogin
 	 * @param string|null $sContent
 	 * @param string|null $sId
 	 *
@@ -141,11 +141,11 @@ class ActivityEntry extends UIBlock
 	/**
 	 * Set the content without any filtering / escaping
 	 *
-	 * @param string $sContent
+	 * @param string|null $sContent
 	 *
 	 * @return $this
 	 */
-	public function SetContent(string $sContent)
+	public function SetContent(?string $sContent)
 	{
 		$this->sContent = $sContent;
 
@@ -206,8 +206,18 @@ class ActivityEntry extends UIBlock
 	public function SetAuthor(string $sAuthorLogin)
 	{
 		$this->sAuthorLogin = $sAuthorLogin;
-		// TODO 2.8.0: Check that this does not return '' when author is the CRON or an extension.
-		$this->sAuthorFriendlyname = UserRights::GetUserFriendlyName($this->sAuthorLogin);
+
+		// Set friendlyname to whatever we have in case $sAuthorLogin is not a valid login (deleted user, cron, ...)
+		$iAuthorId = UserRights::GetUserId($this->sAuthorLogin);
+		if(empty($iAuthorId) === true)
+		{
+			$this->sAuthorFriendlyname = $this->sAuthorLogin;
+		}
+		else
+		{
+			// TODO 2.8.0: Check that this does not return '' when author is the CRON or an extension.
+			$this->sAuthorFriendlyname = UserRights::GetUserFriendlyName($this->sAuthorLogin);
+		}
 		$this->sAuthorInitials = UserRights::GetUserInitials($this->sAuthorLogin);
 		$this->sAuthorPictureAbsUrl = UserRights::GetContactPictureAbsUrl($this->sAuthorLogin, false);
 		$this->bIsFromCurrentUser = UserRights::GetUserId($this->sAuthorLogin) === UserRights::GetUserId();
diff --git a/sources/application/UI/Layout/ActivityPanel/ActivityEntry/CMDBChangeOp/CMDBChangeOpFactory.php b/sources/application/UI/Layout/ActivityPanel/ActivityEntry/CMDBChangeOp/CMDBChangeOpFactory.php
index 9852ff82f3..53c0d0e203 100644
--- a/sources/application/UI/Layout/ActivityPanel/ActivityEntry/CMDBChangeOp/CMDBChangeOpFactory.php
+++ b/sources/application/UI/Layout/ActivityPanel/ActivityEntry/CMDBChangeOp/CMDBChangeOpFactory.php
@@ -25,6 +25,7 @@ use Combodo\iTop\Application\UI\Layout\ActivityPanel\ActivityEntry\ActivityEntry
 use Combodo\iTop\Application\UI\Layout\ActivityPanel\ActivityEntry\EditsEntry;
 use DateTime;
 use iCMDBChangeOp;
+use MetaModel;
 
 /**
  * Class CMDBChangeOpFactory
@@ -52,13 +53,42 @@ class CMDBChangeOpFactory
 	public static function MakeFromCmdbChangeOp(iCMDBChangeOp $oChangeOp)
 	{
 		$oDateTime = DateTime::createFromFormat(AttributeDateTime::GetInternalFormat(), $oChangeOp->Get('date'));
-		$sAuthorFriendlyname = $oChangeOp->Get('userinfo');
 		$sContent = $oChangeOp->GetDescription();
 
-		$oEntry = new ActivityEntry($oDateTime, $sAuthorFriendlyname, $sContent);
+		// Retrieve author login
+		$sAuthorLogin = static::GetUserLoginFromChangeOp($oChangeOp);
+
+		$oEntry = new ActivityEntry($oDateTime, $sAuthorLogin, $sContent);
 		$oEntry->SetType(static::DEFAULT_TYPE)
 			->SetDecorationClasses(static::DEFAULT_DECORATION_CLASSES);
 
 		return $oEntry;
 	}
+
+	/**
+	 * Return the login of the $oChangeOp author or its friendlyname if the user cannot be retrieved.
+	 *
+	 * @param \iCMDBChangeOp $oChangeOp
+	 *
+	 * @return string|null
+	 * @throws \ArchivedObjectException
+	 * @throws \CoreException
+	 */
+	public static function GetUserLoginFromChangeOp(iCMDBChangeOp $oChangeOp)
+	{
+		$iAuthorId = $oChangeOp->Get('user_id');
+		// - Set login in the friendlyname as a fallback
+		$sAuthorLogin = $oChangeOp->Get('userinfo');
+		// - Try to find user login from its ID if present (since iTop 2.8.0)
+		if(empty($iAuthorId) === false)
+		{
+			$oAuthor = MetaModel::GetObject('User', $iAuthorId, false, true);
+			if(empty($oAuthor) === false)
+			{
+				$sAuthorLogin = $oAuthor->Get('login');
+			}
+		}
+
+		return $sAuthorLogin;
+	}
 }
\ No newline at end of file
diff --git a/sources/application/UI/Layout/ActivityPanel/ActivityEntry/CMDBChangeOp/CMDBChangeOpSetAttributeFactory.php b/sources/application/UI/Layout/ActivityPanel/ActivityEntry/CMDBChangeOp/CMDBChangeOpSetAttributeFactory.php
index 3866751570..40dadf7f83 100644
--- a/sources/application/UI/Layout/ActivityPanel/ActivityEntry/CMDBChangeOp/CMDBChangeOpSetAttributeFactory.php
+++ b/sources/application/UI/Layout/ActivityPanel/ActivityEntry/CMDBChangeOp/CMDBChangeOpSetAttributeFactory.php
@@ -23,7 +23,7 @@ namespace Combodo\iTop\Application\UI\Layout\ActivityPanel\ActivityEntry\CMDBCha
 use AttributeDateTime;
 use Combodo\iTop\Application\UI\Layout\ActivityPanel\ActivityEntry\EditsEntry;
 use DateTime;
-use iCMDBChangeOpSetAttribute;
+use iCMDBChangeOp;
 
 /**
  * Class CMDBChangeOpSetAttributeFactory
@@ -33,25 +33,27 @@ use iCMDBChangeOpSetAttribute;
  * @author Guillaume Lajarige <guillaume.lajarige@combodo.com>
  * @package Combodo\iTop\Application\UI\Layout\ActivityPanel\ActivityEntry\CMDBChangeOp
  */
-class CMDBChangeOpSetAttributeFactory
+class CMDBChangeOpSetAttributeFactory extends CMDBChangeOpFactory
 {
 	/**
 	 * Make an EditsEntry from the iCMDBChangeOpSetAttribute $oChangeOp
 	 *
-	 * @param \iCMDBChangeOpSetAttribute $oChangeOp
+	 * @param \iCMDBChangeOp $oChangeOp
 	 *
 	 * @return \Combodo\iTop\Application\UI\Layout\ActivityPanel\ActivityEntry\EditsEntry
 	 * @throws \OQLException
 	 * @throws \Exception
 	 */
-	public static function MakeFromCmdbChangeOp(iCMDBChangeOpSetAttribute $oChangeOp)
+	public static function MakeFromCmdbChangeOp(iCMDBChangeOp $oChangeOp)
 	{
 		$sHostObjectClass = $oChangeOp->Get('objclass');
 		$sAttCode = $oChangeOp->Get('attcode');
 		$oDateTime = DateTime::createFromFormat(AttributeDateTime::GetInternalFormat(), $oChangeOp->Get('date'));
-		$sAuthorFriendlyname = $oChangeOp->Get('userinfo');
 
-		$oEntry = new EditsEntry($oDateTime, $sAuthorFriendlyname, $sHostObjectClass);
+		// Retrieve author login
+		$sAuthorLogin = static::GetUserLoginFromChangeOp($oChangeOp);
+
+		$oEntry = new EditsEntry($oDateTime, $sAuthorLogin, $sHostObjectClass);
 		$oEntry->AddAttribute($sAttCode, $oChangeOp->GetDescription());
 
 		return $oEntry;
diff --git a/sources/application/UI/Layout/ActivityPanel/ActivityEntry/CMDBChangeOp/CMDBChangeOpSetAttributeScalarFactory.php b/sources/application/UI/Layout/ActivityPanel/ActivityEntry/CMDBChangeOp/CMDBChangeOpSetAttributeScalarFactory.php
index e50a32b0c9..1ec8e875d2 100644
--- a/sources/application/UI/Layout/ActivityPanel/ActivityEntry/CMDBChangeOp/CMDBChangeOpSetAttributeScalarFactory.php
+++ b/sources/application/UI/Layout/ActivityPanel/ActivityEntry/CMDBChangeOp/CMDBChangeOpSetAttributeScalarFactory.php
@@ -21,7 +21,7 @@ namespace Combodo\iTop\Application\UI\Layout\ActivityPanel\ActivityEntry\CMDBCha
 
 
 use AttributeDateTime;
-use iCMDBChangeOpSetAttribute;
+use iCMDBChangeOp;
 use Combodo\iTop\Application\UI\Layout\ActivityPanel\ActivityEntry\TransitionEntry;
 use DateTime;
 use MetaModel;
@@ -39,7 +39,7 @@ class CMDBChangeOpSetAttributeScalarFactory extends CMDBChangeOpSetAttributeFact
 	 * @inheritDoc
 	 * @throws \CoreException
 	 */
-	public static function MakeFromCmdbChangeOp(iCMDBChangeOpSetAttribute $oChangeOp)
+	public static function MakeFromCmdbChangeOp(iCMDBChangeOp $oChangeOp)
 	{
 		$sHostObjectClass = $oChangeOp->Get('objclass');
 		$sAttCode = $oChangeOp->Get('attcode');
@@ -48,12 +48,14 @@ class CMDBChangeOpSetAttributeScalarFactory extends CMDBChangeOpSetAttributeFact
 		if($sAttCode === MetaModel::GetStateAttributeCode($sHostObjectClass))
 		{
 			$oDateTime = DateTime::createFromFormat(AttributeDateTime::GetInternalFormat(), $oChangeOp->Get('date'));
-			$sAuthorFriendlyname = $oChangeOp->Get('userinfo');
+
+			// Retrieve author login
+			$sAuthorLogin = static::GetUserLoginFromChangeOp($oChangeOp);
 
 			$sOriginStateLabel = MetaModel::GetStateLabel($sHostObjectClass, $oChangeOp->Get('oldvalue'));
 			$sTargetStateLabel = MetaModel::GetStateLabel($sHostObjectClass, $oChangeOp->Get('newvalue'));
 
-			$oEntry = new TransitionEntry($oDateTime, $sAuthorFriendlyname, $sHostObjectClass, $sOriginStateLabel, $sTargetStateLabel);
+			$oEntry = new TransitionEntry($oDateTime, $sAuthorLogin, $sHostObjectClass, $sOriginStateLabel, $sTargetStateLabel);
 		}
 		else
 		{