diff --git a/service/lib/agama/storage/proposal.rb b/service/lib/agama/storage/proposal.rb
index ec6c63b1f5..af4d8773b4 100644
--- a/service/lib/agama/storage/proposal.rb
+++ b/service/lib/agama/storage/proposal.rb
@@ -66,7 +66,7 @@ def on_calculate(&block)
       #
       # @return [Array<Y2Storage::Device>]
       def available_devices
-        disk_analyzer.candidate_disks
+        disk_analyzer&.candidate_disks || []
       end
 
       # Calculates a new proposal.
@@ -74,6 +74,8 @@ def available_devices
       # @param settings [Agamal::Storage::ProposalSettings] settings to calculate the proposal.
       # @return [Boolean] whether the proposal was correctly calculated.
       def calculate(settings)
+        return false unless storage_manager.probed?
+
         select_target_device(settings) if missing_target_device?(settings)
 
         calculate_proposal(settings)
@@ -170,15 +172,19 @@ def calculate_proposal(settings)
         storage_manager.proposal = proposal
       end
 
-      # @return [Y2Storage::DiskAnalyzer]
+      # @return [Y2Storage::DiskAnalyzer, nil] nil if the system is not probed yet.
       def disk_analyzer
+        return nil unless storage_manager.probed?
+
         storage_manager.probed_disk_analyzer
       end
 
       # Devicegraph representing the system
       #
-      # @return [Y2Storage::Devicegraph]
+      # @return [Y2Storage::Devicegraph, nil] nil if the system is not probed yet.
       def probed_devicegraph
+        return nil unless storage_manager.probed?
+
         storage_manager.probed
       end
 
diff --git a/service/package/rubygem-agama-yast.changes b/service/package/rubygem-agama-yast.changes
index ea1ca93e08..c3fad58bb7 100644
--- a/service/package/rubygem-agama-yast.changes
+++ b/service/package/rubygem-agama-yast.changes
@@ -1,3 +1,8 @@
+-------------------------------------------------------------------
+Thu May 16 15:36:16 UTC 2024 - José Iván López González <jlopez@suse.com>
+
+- Do not probe devices implictly (gh#openSUSE/agama#1226).
+
 -------------------------------------------------------------------
 Wed May 15 12:52:42 UTC 2024 - José Iván López González <jlopez@suse.com>
 
diff --git a/service/test/agama/storage/proposal_test.rb b/service/test/agama/storage/proposal_test.rb
index a9bf94206c..87eb6f166b 100644
--- a/service/test/agama/storage/proposal_test.rb
+++ b/service/test/agama/storage/proposal_test.rb
@@ -155,6 +155,34 @@
         end
       end
     end
+
+    context "if the system has not been probed yet" do
+      before do
+        allow(Y2Storage::StorageManager.instance).to receive(:probed?).and_return(false)
+      end
+
+      it "does not calculate a proposal" do
+        subject.calculate(achievable_settings)
+        expect(Y2Storage::StorageManager.instance.proposal).to be_nil
+      end
+
+      it "does not run the callbacks" do
+        callback1 = proc {}
+        callback2 = proc {}
+
+        subject.on_calculate(&callback1)
+        subject.on_calculate(&callback2)
+
+        expect(callback1).to_not receive(:call)
+        expect(callback2).to_not receive(:call)
+
+        subject.calculate(achievable_settings)
+      end
+
+      it "returns false" do
+        expect(subject.calculate(achievable_settings)).to eq(false)
+      end
+    end
   end
 
   describe "#settings" do