diff --git a/app/src/main/java/com/stevesoltys/seedvault/backend/BackendManager.kt b/app/src/main/java/com/stevesoltys/seedvault/backend/BackendManager.kt
index ebc6d57e..1a7c9fe0 100644
--- a/app/src/main/java/com/stevesoltys/seedvault/backend/BackendManager.kt
+++ b/app/src/main/java/com/stevesoltys/seedvault/backend/BackendManager.kt
@@ -43,6 +43,7 @@ class BackendManager(
             return mBackendProperties
         }
     val isOnRemovableDrive: Boolean get() = backendProperties?.isUsb == true
+    val requiresNetwork: Boolean get() = backendProperties?.requiresNetwork == true
 
     init {
         when (settingsManager.storagePluginType) {
diff --git a/app/src/main/java/com/stevesoltys/seedvault/repo/Checker.kt b/app/src/main/java/com/stevesoltys/seedvault/repo/Checker.kt
index 9943545e..7fda147a 100644
--- a/app/src/main/java/com/stevesoltys/seedvault/repo/Checker.kt
+++ b/app/src/main/java/com/stevesoltys/seedvault/repo/Checker.kt
@@ -42,8 +42,8 @@ internal class Checker(
     private var snapshots: List<Snapshot>? = null
     private val concurrencyLimit: Int
         get() {
-            // TODO determine also based on backendManager
-            return Runtime.getRuntime().availableProcessors()
+            val maxConcurrent = if (backendManager.requiresNetwork) 3 else 42
+            return min(Runtime.getRuntime().availableProcessors(), maxConcurrent)
         }
     var checkerResult: CheckerResult? = null
         private set
diff --git a/app/src/test/java/com/stevesoltys/seedvault/repo/CheckerTest.kt b/app/src/test/java/com/stevesoltys/seedvault/repo/CheckerTest.kt
index 85dc3709..75241f40 100644
--- a/app/src/test/java/com/stevesoltys/seedvault/repo/CheckerTest.kt
+++ b/app/src/test/java/com/stevesoltys/seedvault/repo/CheckerTest.kt
@@ -86,6 +86,7 @@ internal class CheckerTest : TransportTest() {
     fun `check works even with no backup data`() = runBlocking {
         expectLoadingSnapshots(emptyMap())
 
+        every { backendManager.requiresNetwork } returns Random.nextBoolean()
         every { nm.onCheckFinishedWithError(0, 0) } just Runs
 
         assertNull(checker.checkerResult)
@@ -121,6 +122,7 @@ internal class CheckerTest : TransportTest() {
             snapshotHandle2 to snapshot.copy { token = 2 },
         )
         expectLoadingSnapshots(snapshotMap)
+        every { backendManager.requiresNetwork } returns Random.nextBoolean()
 
         val data = ByteArray(0)
         coEvery { loader.loadFile(blobHandle1, null) } returns ByteArrayInputStream(data)
@@ -172,6 +174,7 @@ internal class CheckerTest : TransportTest() {
             },
         )
         expectLoadingSnapshots(snapshotMap)
+        every { backendManager.requiresNetwork } returns Random.nextBoolean()
 
         coEvery { loader.loadFile(blobHandle1, null) } returns ByteArrayInputStream(data1)
         coEvery { loader.loadFile(blobHandle2, null) } throws GeneralSecurityException()
@@ -220,6 +223,7 @@ internal class CheckerTest : TransportTest() {
         val expectedSize = blob1.length.toLong() + blob2.length.toLong()
 
         expectLoadingSnapshots(snapshotMap)
+        every { backendManager.requiresNetwork } returns Random.nextBoolean()
 
         coEvery { loader.loadFile(blobHandle1, null) } returns ByteArrayInputStream(data1)
         coEvery { loader.loadFile(blobHandle2, null) } returns ByteArrayInputStream(data2)
@@ -257,6 +261,7 @@ internal class CheckerTest : TransportTest() {
             },
         )
         expectLoadingSnapshots(snapshotMap)
+        every { backendManager.requiresNetwork } returns Random.nextBoolean()
 
         // only loading app data, not other blobs
         coEvery { loader.loadFile(appDataBlobHandle1, null) } throws SecurityException()