diff --git a/src/xapi/index.js b/src/xapi/index.js
index 8221e9856..1c0d90a64 100644
--- a/src/xapi/index.js
+++ b/src/xapi/index.js
@@ -1603,6 +1603,10 @@ export default class Xapi extends XapiBase {
     type = 'user',
     xenstore_data = undefined
   } = {}) {
+    if (sr === NULL_REF) {
+      throw new Error('SR required to create VDI')
+    }
+
     sr = this.getObject(sr)
     debug(`Creating VDI ${name_label} on ${sr.name_label}`)
 
@@ -2152,7 +2156,7 @@ export default class Xapi extends XapiBase {
     return this.createTemporaryVdiOnSr(stream, pbd.SR, name_label, name_description)
   }
 
-  async findAvailableSharedSr (minSize) {
+  findAvailableSharedSr (minSize) {
     return find(
       this.objects.all,
       obj => obj.$type === 'sr' && obj.shared && canSrHaveNewVdiOfSize(obj, minSize)
diff --git a/src/xapi/mixins/patching.js b/src/xapi/mixins/patching.js
index 5795f44ed..ef2d2b065 100644
--- a/src/xapi/mixins/patching.js
+++ b/src/xapi/mixins/patching.js
@@ -273,7 +273,7 @@ export default {
 
     // If no hostId provided, try and find a shared SR
     if (!hostId) {
-      const sr = await this.findAvailableSharedSr(stream.length)
+      const sr = this.findAvailableSharedSr(stream.length)
 
       if (!sr) {
         return