diff --git a/Tusker/CoreData/MastodonCachePersistentStore.swift b/Tusker/CoreData/MastodonCachePersistentStore.swift
index e8846675..2fc5938c 100644
--- a/Tusker/CoreData/MastodonCachePersistentStore.swift
+++ b/Tusker/CoreData/MastodonCachePersistentStore.swift
@@ -53,7 +53,7 @@ class MastodonCachePersistentStore: NSPersistentContainer {
             storeDescription.type = NSInMemoryStoreType
             persistentStoreDescriptions = [storeDescription]
         } else {
-            super.init(name: "\(accountInfo!.id)_cache", managedObjectModel: MastodonCachePersistentStore.managedObjectModel)
+            super.init(name: "\(accountInfo!.persistenceKey)_cache", managedObjectModel: MastodonCachePersistentStore.managedObjectModel)
         }
         
         loadPersistentStores { (description, error) in
diff --git a/Tusker/LocalData.swift b/Tusker/LocalData.swift
index ba4a7e89..4da80d77 100644
--- a/Tusker/LocalData.swift
+++ b/Tusker/LocalData.swift
@@ -208,6 +208,12 @@ extension LocalData {
             self.accessToken = accessToken
         }
         
+        /// A filename-safe string for this account
+        var persistenceKey: String {
+            // slashes are not allowed in the persistent store coordinator name
+            id.replacingOccurrences(of: "/", with: "_")
+        }
+        
         func hash(into hasher: inout Hasher) {
             hasher.combine(id)
         }