--- a/browser/base/content/browser-siteIdentity.js
+++ b/browser/base/content/browser-siteIdentity.js
@@ -206,29 +206,23 @@ var gIdentityHandler = {
       permissionAnchors[anchor.getAttribute("data-permission-id")] = anchor;
     }
     return this._permissionAnchors = permissionAnchors;
   },
 
   /**
    * Handles clicks on the "Clear Cookies and Site Data" button.
    */
-  async clearSiteData(event) {
+  clearSiteData(event) {
     if (!this._uriHasHost) {
       return;
     }
 
-    let host = this._uri.host;
-
-    // Site data could have changed while the identity popup was open,
-    // reload again to be sure.
-    await SiteDataManager.updateSites();
-
-    let baseDomain = SiteDataManager.getBaseDomainFromHost(host);
-    let siteData = await SiteDataManager.getSites(baseDomain);
+    let baseDomain = SiteDataManager.getBaseDomainFromHost(this._uri.host);
+    let siteData = SiteDataManager.getSites(baseDomain);
 
     // Hide the popup before showing the removal prompt, to
     // avoid a pretty ugly transition. Also hide it even
     // if the update resulted in no site data, to keep the
     // illusion that clicking the button had an effect.
     PanelMultiView.hidePopup(this._identityPopup);
 
     if (siteData && siteData.length) {
@@ -609,24 +603,22 @@ var gIdentityHandler = {
    * applicable
    */
   refreshIdentityPopup() {
     // Update cookies and site data information and show the
     // "Clear Site Data" button if the site is storing local data.
     this._clearSiteDataFooter.hidden = true;
     if (this._uriHasHost) {
       let host = this._uri.host;
-      SiteDataManager.updateSites().then(async () => {
-        let baseDomain = SiteDataManager.getBaseDomainFromHost(host);
-        let siteData = await SiteDataManager.getSites(baseDomain);
+      let baseDomain = SiteDataManager.getBaseDomainFromHost(host);
+      let siteData = SiteDataManager.getSites(baseDomain);
 
-        if (siteData && siteData.length) {
-          this._clearSiteDataFooter.hidden = false;
-        }
-      });
+      if (siteData && siteData.length) {
+        this._clearSiteDataFooter.hidden = false;
+      }
     }
 
     // Update "Learn More" for Mixed Content Blocking and Insecure Login Forms.
     let baseURL = Services.urlFormatter.formatURLPref("app.support.baseURL");
     this._identityPopupMixedContentLearnMore
         .setAttribute("href", baseURL + "mixed-content");
     this._identityPopupInsecureLoginFormsLearnMore
         .setAttribute("href", baseURL + "insecure-password");

--- a/browser/base/content/pageinfo/security.js
+++ b/browser/base/content/pageinfo/security.js
@@ -127,19 +127,19 @@ var security = {
 
   // Find the secureBrowserUI object (if present)
   _getSecurityUI() {
     if (window.opener.gBrowser)
       return window.opener.gBrowser.securityUI;
     return null;
   },
 
-  async _updateSiteDataInfo() {
+  _updateSiteDataInfo() {
     // Save site data info for deleting.
-    this.siteData = await SiteDataManager.getSites(
+    this.siteData = SiteDataManager.getSites(
       SiteDataManager.getBaseDomainFromHost(this.uri.host));
 
     let pageInfoBundle = document.getElementById("pageinfobundle");
     let clearSiteDataButton = document.getElementById("security-clear-sitedata");
     let siteDataLabel = document.getElementById("security-privacy-sitedata-value");
 
     if (!this.siteData.length) {
       let noStr = pageInfoBundle.getString("securitySiteDataNo");
@@ -246,17 +246,17 @@ function securityOnLoad(uri, windowInfo)
     viewCert.collapsed = true;
 
   /* Set Privacy & History section text */
   var yesStr = pageInfoBundle.getString("yes");
   var noStr = pageInfoBundle.getString("no");
 
   // Only show quota usage data for websites, not internal sites.
   if (uri.scheme == "http" || uri.scheme == "https") {
-    SiteDataManager.updateSites().then(() => security._updateSiteDataInfo());
+    security._updateSiteDataInfo();
   } else {
     document.getElementById("security-privacy-sitedata-row").hidden = true;
   }
 
   setText("security-privacy-passwords-value",
           realmHasPasswords(uri) ? yesStr : noStr);
 
   var visitCount = previousVisitCount(info.hostName);

--- a/browser/components/preferences/clearSiteData.js
+++ b/browser/components/preferences/clearSiteData.js
@@ -17,30 +17,28 @@ var gClearSiteDataDialog = {
   },
 
   async init() {
     this._clearButton = document.getElementById("clearButton");
     this._cancelButton = document.getElementById("cancelButton");
     this._clearSiteDataCheckbox = document.getElementById("clearSiteData");
     this._clearCacheCheckbox = document.getElementById("clearCache");
 
-    // We'll block init() on this because the result values may impact
-    // subdialog sizing.
-    await Promise.all([
-      SiteDataManager.getTotalUsage().then(bytes => {
-        let [amount, unit] = DownloadUtils.convertByteUnits(bytes);
-        document.l10n.setAttributes(this._clearSiteDataCheckbox,
-          "clear-site-data-cookies-with-data", { amount, unit });
-      }),
-      SiteDataManager.getCacheSize().then(bytes => {
-        let [amount, unit] = DownloadUtils.convertByteUnits(bytes);
-        document.l10n.setAttributes(this._clearCacheCheckbox,
-          "clear-site-data-cache-with-data", { amount, unit });
-      }),
-    ]);
+    // Show quota managed storage size in parentheses.
+    let bytes = SiteDataManager.getTotalUsage();
+    let [amount, unit] = DownloadUtils.convertByteUnits(bytes);
+    document.l10n.setAttributes(this._clearSiteDataCheckbox,
+      "clear-site-data-cookies-with-data", { amount, unit });
+
+    // Show cache size in parentheses.
+    bytes = await SiteDataManager.getCacheSize();
+    [amount, unit] = DownloadUtils.convertByteUnits(bytes);
+    document.l10n.setAttributes(this._clearCacheCheckbox,
+      "clear-site-data-cache-with-data", { amount, unit });
+
     await document.l10n.translateElements([
       this._clearCacheCheckbox,
       this._clearSiteDataCheckbox
     ]);
 
     window.addEventListener("keypress", this.onWindowKeyPress);
 
     this._cancelButton.addEventListener("command", window.close);
@@ -60,20 +58,20 @@ var gClearSiteDataDialog = {
       !(this._clearSiteDataCheckbox.checked || this._clearCacheCheckbox.checked);
   },
 
   onClear() {
     let allowed = true;
 
     if (this._clearCacheCheckbox.checked && allowed) {
       SiteDataManager.removeCache();
-      // If we're not clearing site data, we need to tell the
-      // SiteDataManager to signal that it's updating.
+      // If the site data manager will not update site data or cookies,
+      // we need to manually signal the preferences UI that it should update.
       if (!this._clearSiteDataCheckbox.checked) {
-        SiteDataManager.updateSites();
+        Services.obs.notifyObservers(null, "sitedatamanager:sites-updated");
       }
     }
 
     if (this._clearSiteDataCheckbox.checked) {
       allowed = SiteDataManager.promptSiteDataRemoval(window);
       if (allowed) {
         SiteDataManager.removeSiteData();
       }

--- a/browser/components/preferences/in-content/privacy.js
+++ b/browser/components/preferences/in-content/privacy.js
@@ -357,24 +357,23 @@ var gPrivacyPane = {
       if (AlertsServiceDND.manualDoNotDisturb) {
         let notificationsDoNotDisturb =
           document.getElementById("notificationsDoNotDisturb");
         notificationsDoNotDisturb.setAttribute("checked", true);
       }
     }
 
     Services.obs.addObserver(this, "sitedatamanager:sites-updated");
-    Services.obs.addObserver(this, "sitedatamanager:updating-sites");
     let unload = () => {
       window.removeEventListener("unload", unload);
       Services.obs.removeObserver(this, "sitedatamanager:sites-updated");
-      Services.obs.removeObserver(this, "sitedatamanager:updating-sites");
     };
     window.addEventListener("unload", unload);
-    SiteDataManager.updateSites();
+    this.updateTotalDataSizeLabel();
+
     setEventListener("clearSiteDataButton", "command",
       gPrivacyPane.clearSiteData);
     setEventListener("siteDataSettings", "command",
       gPrivacyPane.showSiteDataSettings);
     let url = Services.urlFormatter.formatURLPref("app.support.baseURL") + "storage-permissions";
     document.getElementById("siteDataLearnMoreLink").setAttribute("href", url);
 
     let notificationInfoURL =
@@ -1014,29 +1013,18 @@ var gPrivacyPane = {
     gSubDialog.open("chrome://browser/content/preferences/permissions.xul",
       null, params);
   },
 
   showSiteDataSettings() {
     gSubDialog.open("chrome://browser/content/preferences/siteDataSettings.xul");
   },
 
-  toggleSiteData(shouldShow) {
-    let clearButton = document.getElementById("clearSiteDataButton");
-    let settingsButton = document.getElementById("siteDataSettings");
-    clearButton.disabled = !shouldShow;
-    settingsButton.disabled = !shouldShow;
-  },
-
-  showSiteDataLoading() {
-    let totalSiteDataSizeLabel = document.getElementById("totalSiteDataSize");
-    document.l10n.setAttributes(totalSiteDataSizeLabel, "sitedata-total-size-calculating");
-  },
-
-  updateTotalDataSizeLabel(siteDataUsage) {
+  updateTotalDataSizeLabel() {
+    let siteDataUsage = SiteDataManager.getTotalUsage();
     SiteDataManager.getCacheSize().then(function(cacheUsage) {
       let totalSiteDataSizeLabel = document.getElementById("totalSiteDataSize");
       let totalUsage = siteDataUsage + cacheUsage;
       let [value, unit] = DownloadUtils.convertByteUnits(totalUsage);
       document.l10n.setAttributes(totalSiteDataSizeLabel, "sitedata-total-size", {
         value,
         unit
       });
@@ -1619,26 +1607,18 @@ var gPrivacyPane = {
       }
     }
     Preferences.get(PREF_UPLOAD_ENABLED).on("change", updateStudyCheckboxState);
     updateStudyCheckboxState();
   },
 
   observe(aSubject, aTopic, aData) {
     switch (aTopic) {
-      case "sitedatamanager:updating-sites":
-        // While updating, we want to disable this section and display loading message until updated
-        this.toggleSiteData(false);
-        this.showSiteDataLoading();
-        break;
-
       case "sitedatamanager:sites-updated":
-        this.toggleSiteData(true);
-        SiteDataManager.getTotalUsage()
-          .then(this.updateTotalDataSizeLabel.bind(this));
+        this.updateTotalDataSizeLabel();
         break;
     }
   },
 
   // Accessibility checkbox helpers
   _initA11yState() {
     this._initA11yString();
     let checkbox = document.getElementById("a11yPrivacyCheckbox");

--- a/browser/components/preferences/siteDataSettings.js
+++ b/browser/components/preferences/siteDataSettings.js
@@ -92,55 +92,69 @@ let gSiteDataSettings = {
     this._absoluteTimeFormat = new Services.intl.DateTimeFormat(undefined, {
       dateStyle: "short", timeStyle: "short",
     });
 
     this._relativeTimeFormat = new Services.intl.RelativeTimeFormat(undefined, {});
 
     this._list = document.getElementById("sitesList");
     this._searchBox = document.getElementById("searchBox");
-    SiteDataManager.getSites().then(sites => {
-      this._sites = sites;
-      let sortCol = document.querySelector("treecol[data-isCurrentSortCol=true]");
-      this._sortSites(this._sites, sortCol);
-      this._buildSitesList(this._sites);
-      Services.obs.notifyObservers(null, "sitedata-settings-init");
-    });
+    this._sites = SiteDataManager.getSites();
+    let sortCol = document.querySelector("treecol[data-isCurrentSortCol=true]");
+    this._sortSites(this._sites, sortCol, true);
+    this._buildSitesList(this._sites);
+    Services.obs.notifyObservers(null, "sitedata-settings-init");
+
+    Services.obs.addObserver(this, "sitedatamanager:sites-updated");
 
     setEventListener("sitesList", "select", this.onSelect);
     setEventListener("hostCol", "click", this.onClickTreeCol);
     setEventListener("usageCol", "click", this.onClickTreeCol);
     setEventListener("lastAccessedCol", "click", this.onClickTreeCol);
     setEventListener("cookiesCol", "click", this.onClickTreeCol);
     setEventListener("cancel", "command", this.close);
     setEventListener("save", "command", this.saveChanges);
     setEventListener("searchBox", "command", this.onCommandSearch);
     setEventListener("removeAll", "command", this.onClickRemoveAll);
     setEventListener("removeSelected", "command", this.onClickRemoveSelected);
   },
 
+  uninit() {
+    Services.obs.removeObserver(this, "sitedatamanager:sites-updated");
+  },
+
+  observe(subject, topic, data) {
+    if (topic != "sitedatamanager:sites-updated") {
+      return;
+    }
+    this._sites = SiteDataManager.getSites();
+    let sortCol = document.querySelector("treecol[data-isCurrentSortCol=true]");
+    this._sortSites(this._sites, sortCol, false);
+    this._buildSitesList(this._sites);
+  },
+
   _updateButtonsState() {
     let items = this._list.getElementsByTagName("richlistitem");
     let removeSelectedBtn = document.getElementById("removeSelected");
     let removeAllBtn = document.getElementById("removeAll");
     removeSelectedBtn.disabled = this._list.selectedItems.length == 0;
     removeAllBtn.disabled = items.length == 0;
 
     let l10nId = this._searchBox.value ? "site-data-remove-shown" : "site-data-remove-all";
     document.l10n.setAttributes(removeAllBtn, l10nId);
   },
 
   /**
    * @param sites {Array}
    * @param col {XULElement} the <treecol> being sorted on
    */
-  _sortSites(sites, col) {
+  _sortSites(sites, col, flipDirection) {
     let isCurrentSortCol = col.getAttribute("data-isCurrentSortCol");
     let sortDirection = col.getAttribute("data-last-sortDirection") || "ascending";
-    if (isCurrentSortCol) {
+    if (flipDirection && isCurrentSortCol) {
       // Sort on the current column, flip the sorting direction
       sortDirection = sortDirection === "ascending" ? "descending" : "ascending";
     }
 
     let sortFunc = null;
     switch (col.id) {
       case "hostCol":
         sortFunc = (a, b) => {
@@ -249,17 +263,17 @@ let gSiteDataSettings = {
     }
   },
 
   close() {
     window.close();
   },
 
   onClickTreeCol(e) {
-    this._sortSites(this._sites, e.target);
+    this._sortSites(this._sites, e.target, true);
     this._buildSitesList(this._sites);
     this._list.clearSelection();
   },
 
   onCommandSearch() {
     this._buildSitesList(this._sites);
     this._list.clearSelection();
   },

--- a/browser/components/preferences/siteDataSettings.xul
+++ b/browser/components/preferences/siteDataSettings.xul
@@ -11,16 +11,17 @@
 
 <window id="SiteDataSettingsDialog" windowtype="Browser:SiteDataSettings"
         data-l10n-id="site-data-settings-window"
         data-l10n-attrs="title"
         class="windowDialog"
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
         style="width: 45em;"
         onload="gSiteDataSettings.init();"
+        onunload="gSiteDataSettings.uninit();"
         onkeypress="gSiteDataSettings.onKeyPress(event);"
         persist="screenX screenY width height">
 
   <link rel="localization" href="branding/brand.ftl"/>
   <link rel="localization" href="browser/preferences/siteDataSettings.ftl"/>
   <script type="application/javascript" src="chrome://global/content/l10n.js"></script>
 
   <script src="chrome://browser/content/preferences/siteDataSettings.js"/>