diff --git a/packages/nc-gui/components/cell/User.vue b/packages/nc-gui/components/cell/User.vue
index 8a6c1e1bb3..93fc307cec 100644
--- a/packages/nc-gui/components/cell/User.vue
+++ b/packages/nc-gui/components/cell/User.vue
@@ -32,8 +32,12 @@ const activeCell = inject(ActiveCellInj, ref(false))
 
 const basesStore = useBases()
 
+const baseStore = useBase()
+
 const { basesUser } = storeToRefs(basesStore)
 
+const { idUserMap } = storeToRefs(baseStore)
+
 const baseUsers = computed(() => (meta.value.base_id ? basesUser.value.get(meta.value.base_id) || [] : []))
 
 // use both ActiveCellInj or EditModeInj to determine the active state
@@ -303,6 +307,11 @@ const filterOption = (input: string, option: any) => {
     return searchVal.toLowerCase().includes(input.toLowerCase())
   }
 }
+
+// check if user is part of the base
+const isCollaborator = (userIdOrEmail) => {
+  return !idUserMap.value?.[userIdOrEmail]?.deleted
+}
 </script>
 
 <template>
@@ -347,6 +356,7 @@ const filterOption = (input: string, option: any) => {
                     :name="op.display_name?.trim() ? op.display_name?.trim() : ''"
                     :email="op.email"
                     class="!text-[0.65rem]"
+                    :disabled="!isCollaborator(op.id)"
                   />
                 </div>
                 <NcTooltip class="truncate max-w-full" show-on-truncate-only>
@@ -360,6 +370,9 @@ const filterOption = (input: string, option: any) => {
                       whiteSpace: 'nowrap',
                       display: 'inline',
                     }"
+                    :class="{
+                      'text-gray-600': !isCollaborator(op.id || op.email),
+                    }"
                   >
                     {{ op.display_name?.trim() || op.email }}
                   </span>
@@ -408,6 +421,7 @@ const filterOption = (input: string, option: any) => {
             >
               <div class="flex-none">
                 <GeneralUserIcon
+                  :disabled="!isCollaborator(selectedOpt.value)"
                   size="auto"
                   :name="!selectedOpt.label?.includes('@') ? selectedOpt.label.trim() : ''"
                   :email="selectedOpt.label"
@@ -425,6 +439,9 @@ const filterOption = (input: string, option: any) => {
                     whiteSpace: 'nowrap',
                     display: 'inline',
                   }"
+                  :class="{
+                    'text-gray-600': !isCollaborator(selectedOpt.value),
+                  }"
                 >
                   {{ selectedOpt.label }}
                 </span>
@@ -540,9 +557,16 @@ const filterOption = (input: string, option: any) => {
                   :name="!label?.includes('@') ? label.trim() : ''"
                   :email="label"
                   class="!text-[0.65rem]"
+                  :disabled="!isCollaborator(val)"
                 />
               </div>
-              {{ label }}
+              <span
+                :class="{
+                  'text-gray-600': !isCollaborator(val),
+                }"
+              >
+                {{ label }}
+              </span>
             </span>
           </a-tag>
         </template>
diff --git a/packages/nc-gui/components/general/UserIcon.vue b/packages/nc-gui/components/general/UserIcon.vue
index 61d9232e73..8ce6118caa 100644
--- a/packages/nc-gui/components/general/UserIcon.vue
+++ b/packages/nc-gui/components/general/UserIcon.vue
@@ -6,11 +6,13 @@ const props = withDefaults(
     size?: 'small' | 'medium' | 'base' | 'large' | 'xlarge' | 'auto'
     name?: string
     email?: string
+    disabled?: boolean
   }>(),
   {
     size: 'medium',
     name: '',
     email: '',
+    disabled: false,
   },
 )
 
@@ -19,11 +21,19 @@ const { size, email } = toRefs(props)
 const displayName = computed(() => props.name?.trim() || '')
 
 const backgroundColor = computed(() => {
+  if (props.disabled) {
+    return '#bbbbbb'
+  }
+
   // in comments we need to generate user icon from email
   return displayName.value ? stringToColor(displayName.value) : email.value ? stringToColor(email.value) : '#FFFFFF'
 })
 
 const usernameInitials = computed(() => {
+  if (props.disabled) {
+    return ''
+  }
+
   const displayNameSplit = displayName.value?.split(' ').filter((name) => name) ?? []
 
   if (displayNameSplit.length > 0) {
diff --git a/packages/nc-gui/components/workspace/CollaboratorsList.vue b/packages/nc-gui/components/workspace/CollaboratorsList.vue
index a2ed3d6822..02415befe1 100644
--- a/packages/nc-gui/components/workspace/CollaboratorsList.vue
+++ b/packages/nc-gui/components/workspace/CollaboratorsList.vue
@@ -7,6 +7,8 @@ const props = defineProps<{
 
 const { workspaceRoles } = useRoles()
 
+const { user } = useGlobal()
+
 const workspaceStore = useWorkspace()
 
 const { removeCollaborator, updateCollaborator: _updateCollaborator, loadWorkspace } = workspaceStore
@@ -35,8 +37,6 @@ const isOnlyOneOwner = computed(() => {
   return collaborators.value?.filter((collab) => collab.roles === WorkspaceUserRoles.OWNER).length === 1
 })
 
-const { isUIAllowed } = useRoles()
-
 const { t } = useI18n()
 
 const inviteDlg = ref(false)
@@ -289,25 +289,20 @@ const isDeleteOrUpdateAllowed = (user) => {
 
                     <a-menu-divider class="my-1.5" />
                   </template>
-                  <NcMenuItem
-                    v-if="isUIAllowed('transferWorkspaceOwnership')"
-                    :disabled="!isDeleteOrUpdateAllowed(record)"
-                    data-testid="nc-admin-org-user-assign-admin"
-                    @click="updateCollaborator(record, WorkspaceUserRoles.OWNER)"
-                  >
-                    <GeneralIcon :class="{ 'text-gray-800': isDeleteOrUpdateAllowed(record) }" icon="user" />
-                    <span>{{ $t('labels.assignAs') }}</span>
-                    <RolesBadge :border="false" :show-icon="false" role="owner" :disabled="!isDeleteOrUpdateAllowed(record)" />
-                  </NcMenuItem>
-
-                  <NcMenuItem
-                    :disabled="!isDeleteOrUpdateAllowed(record)"
-                    :class="{ '!text-red-500 !hover:bg-red-50': isDeleteOrUpdateAllowed(record) }"
-                    @click="removeCollaborator(record.id, currentWorkspace?.id)"
-                  >
-                    <MaterialSymbolsDeleteOutlineRounded />
-                    Remove user
-                  </NcMenuItem>
+                  <NcTooltip :disabled="!isOnlyOneOwner || record.roles !== WorkspaceUserRoles.OWNER">
+                    <template #title>
+                      Each workspace must have at least one owner. Please assign another user as the Owner before leaving the
+                      workspace. If you are the last member, consider deleting the workspace instead.
+                    </template>
+                    <NcMenuItem
+                      :disabled="!isDeleteOrUpdateAllowed(record)"
+                      :class="{ '!text-red-500 !hover:bg-red-50': isDeleteOrUpdateAllowed(record) }"
+                      @click="removeCollaborator(record.id, currentWorkspace?.id)"
+                    >
+                      <MaterialSymbolsDeleteOutlineRounded />
+                      {{ record.id === user.id ? 'Leave workspace' : 'Remove user' }}
+                    </NcMenuItem>
+                  </NcTooltip>
                 </NcMenu>
               </template>
             </NcDropdown>
diff --git a/packages/nc-gui/store/base.ts b/packages/nc-gui/store/base.ts
index 9f88f00463..e31419705a 100644
--- a/packages/nc-gui/store/base.ts
+++ b/packages/nc-gui/store/base.ts
@@ -26,6 +26,14 @@ export const useBase = defineStore('baseStore', () => {
 
   const tablesStore = useTablesStore()
 
+  const idUserMap = computed(() => {
+    return (basesStore.basesUser.get(baseId.value) || []).reduce((acc, user) => {
+      acc[user.id] = user
+      acc[user.email] = user
+      return acc
+    }, {} as Record<string, any>)
+  })
+
   // todo: refactor
   const sharedProject = ref<BaseType>()
 
@@ -297,6 +305,7 @@ export const useBase = defineStore('baseStore', () => {
     baseUrl,
     getBaseType,
     navigateToProjectPage,
+    idUserMap,
   }
 })