diff --git a/e2e/harmony/lanes/lane-export-skip-main-history.e2e.ts b/e2e/harmony/lanes/lane-export-skip-main-history.e2e.ts
new file mode 100644
index 000000000000..6d42f401aec9
--- /dev/null
+++ b/e2e/harmony/lanes/lane-export-skip-main-history.e2e.ts
@@ -0,0 +1,203 @@
+import chai, { expect } from 'chai';
+import { Helper } from '@teambit/legacy.e2e-helper';
+import chaiFs from 'chai-fs';
+
+chai.use(chaiFs);
+
+describe('lane export skips main history objects', function () {
+  this.timeout(0);
+  let helper: Helper;
+  before(() => {
+    helper = new Helper();
+  });
+  after(() => {
+    helper.scopeHelper.destroy();
+  });
+
+  describe('lane in scope-L with components in scope-C, main advances, merge main into lane', () => {
+    let laneScope: string;
+    let laneScopePath: string;
+    let mainSnap1: string;
+    let mainSnap2: string;
+    let mainSnap3: string;
+    let mainSnap4: string;
+    let laneSnap: string;
+    let mergeSnap: string;
+
+    before(() => {
+      // scope-C: components' home scope (default remote)
+      helper.scopeHelper.setWorkspaceWithRemoteScope();
+      // scope-L: the lane's home scope (separate)
+      const newScope = helper.scopeHelper.getNewBareScope();
+      laneScope = newScope.scopeName;
+      laneScopePath = newScope.scopePath;
+      helper.scopeHelper.addRemoteScope(laneScopePath);
+      helper.scopeHelper.addRemoteScope(laneScopePath, helper.scopes.remotePath);
+      helper.scopeHelper.addRemoteScope(helper.scopes.remotePath, laneScopePath);
+
+      // build several main snaps in scope-C
+      helper.fixtures.populateComponents(1);
+      helper.command.tagAllWithoutBuild();
+      mainSnap1 = helper.command.getHead('comp1');
+      helper.command.tagAllWithoutBuild('--unmodified');
+      mainSnap2 = helper.command.getHead('comp1');
+      helper.command.tagAllWithoutBuild('--unmodified');
+      mainSnap3 = helper.command.getHead('comp1');
+      helper.command.export();
+
+      // create the lane in scope-L (off main, so its base is mainSnap3)
+      helper.command.createLane('dev', `--scope ${laneScope}`);
+      helper.command.snapAllComponentsWithoutBuild('--unmodified');
+      laneSnap = helper.command.getHeadOfLane('dev', 'comp1');
+      helper.command.export();
+      const laneWorkspace = helper.scopeHelper.cloneWorkspace();
+
+      // main advances further (more snaps that the lane never saw)
+      helper.command.switchLocalLane('main');
+      helper.command.tagAllWithoutBuild('--unmodified');
+      mainSnap4 = helper.command.getHead('comp1');
+      helper.command.export();
+
+      // back to lane, pick up new main, merge main in (no squash; that's the default for lane->merge)
+      helper.scopeHelper.getClonedWorkspace(laneWorkspace);
+      helper.command.import();
+      helper.command.mergeLane('main', '--auto-merge-resolve theirs');
+      mergeSnap = helper.command.getHeadOfLane('dev', 'comp1');
+      helper.command.export();
+    });
+
+    describe('what was pushed to lane scope (scope-L)', () => {
+      it('should contain the merge snap', () => {
+        expect(() => helper.command.catObject(mergeSnap, false, laneScopePath)).to.not.throw();
+      });
+
+      it('should contain the lane-only snap', () => {
+        expect(() => helper.command.catObject(laneSnap, false, laneScopePath)).to.not.throw();
+      });
+
+      it('should NOT contain main snaps that the lane was based on', () => {
+        expect(() => helper.command.catObject(mainSnap1, false, laneScopePath)).to.throw();
+        expect(() => helper.command.catObject(mainSnap2, false, laneScopePath)).to.throw();
+        expect(() => helper.command.catObject(mainSnap3, false, laneScopePath)).to.throw();
+      });
+
+      it('should NOT contain the new main snap that got merged in', () => {
+        expect(() => helper.command.catObject(mainSnap4, false, laneScopePath)).to.throw();
+      });
+    });
+
+    describe('what stayed on component home scope (scope-C)', () => {
+      it('should still contain all main snaps', () => {
+        expect(() => helper.command.catObject(mainSnap1, false, helper.scopes.remotePath)).to.not.throw();
+        expect(() => helper.command.catObject(mainSnap2, false, helper.scopes.remotePath)).to.not.throw();
+        expect(() => helper.command.catObject(mainSnap3, false, helper.scopes.remotePath)).to.not.throw();
+        expect(() => helper.command.catObject(mainSnap4, false, helper.scopes.remotePath)).to.not.throw();
+      });
+    });
+
+    describe('fresh consumer imports the lane', () => {
+      before(() => {
+        helper.scopeHelper.reInitWorkspace();
+        helper.scopeHelper.addRemoteScope();
+        helper.scopeHelper.addRemoteScope(laneScopePath);
+        helper.command.runCmd(`bit lane import ${laneScope}/dev -x`);
+      });
+
+      it('bit status should not throw', () => {
+        expect(() => helper.command.status()).to.not.throw();
+      });
+
+      it('checkout HEAD should not throw', () => {
+        expect(() => helper.command.checkoutHead()).to.not.throw();
+      });
+
+      it('bit log should not throw and should show the full history including main snaps', () => {
+        // bit log walks parents into main history. lane scope does not have those snaps,
+        // so the read path must fetch them from each component's home scope (scope-C)
+        // transparently. importMissingHistory is server-side; this fallback is client-side.
+        let log;
+        expect(() => {
+          log = helper.command.logParsed('comp1');
+        }).to.not.throw();
+        const hashes = log.map((l: any) => l.hash);
+        expect(hashes).to.include(mergeSnap);
+        expect(hashes).to.include(laneSnap);
+        expect(hashes).to.include(mainSnap4);
+        // pre-lane main history should also be reachable
+        expect(hashes).to.include(mainSnap3);
+        expect(hashes).to.include(mainSnap2);
+        expect(hashes).to.include(mainSnap1);
+      });
+    });
+  });
+
+  describe('sanity: regular (non-merge) lane export still includes lane-only history fully', () => {
+    let laneScope: string;
+    let laneScopePath: string;
+    let snap1: string;
+    let snap2: string;
+
+    before(() => {
+      helper.scopeHelper.setWorkspaceWithRemoteScope();
+      const newScope = helper.scopeHelper.getNewBareScope();
+      laneScope = newScope.scopeName;
+      laneScopePath = newScope.scopePath;
+      helper.scopeHelper.addRemoteScope(laneScopePath);
+      helper.scopeHelper.addRemoteScope(laneScopePath, helper.scopes.remotePath);
+      helper.scopeHelper.addRemoteScope(helper.scopes.remotePath, laneScopePath);
+
+      // create a lane right away (no main tags), so all snaps are lane-origin
+      helper.command.createLane('dev', `--scope ${laneScope}`);
+      helper.fixtures.populateComponents(1);
+      helper.command.snapAllComponentsWithoutBuild();
+      snap1 = helper.command.getHeadOfLane('dev', 'comp1');
+      helper.command.snapAllComponentsWithoutBuild('--unmodified');
+      snap2 = helper.command.getHeadOfLane('dev', 'comp1');
+      helper.command.export();
+    });
+
+    it('lane scope should contain all lane-origin snaps', () => {
+      expect(() => helper.command.catObject(snap1, false, laneScopePath)).to.not.throw();
+      expect(() => helper.command.catObject(snap2, false, laneScopePath)).to.not.throw();
+    });
+  });
+
+  describe('sanity: existing main-merge with no scope split still works (lane and components share scope)', () => {
+    let mainSnap: string;
+    let mergeSnap: string;
+
+    before(() => {
+      helper.scopeHelper.setWorkspaceWithRemoteScope();
+      helper.fixtures.populateComponents(1);
+      helper.command.tagAllWithoutBuild();
+      mainSnap = helper.command.getHead('comp1');
+      helper.command.export();
+
+      helper.command.createLane('dev');
+      helper.command.snapAllComponentsWithoutBuild('--unmodified');
+      helper.command.export();
+      const laneWorkspace = helper.scopeHelper.cloneWorkspace();
+
+      helper.command.switchLocalLane('main');
+      helper.command.tagAllWithoutBuild('--unmodified');
+      helper.command.export();
+
+      helper.scopeHelper.getClonedWorkspace(laneWorkspace);
+      helper.command.import();
+      helper.command.mergeLane('main', '--auto-merge-resolve theirs');
+      mergeSnap = helper.command.getHeadOfLane('dev', 'comp1');
+      helper.command.export();
+    });
+
+    it('the shared remote scope should contain both the merge snap and the old main snap (same-scope case)', () => {
+      // When lane scope == component scope, filtering by origin doesn't apply: everything already
+      // belongs to this scope. Both objects should be present.
+      expect(() => helper.command.catObject(mergeSnap, false, helper.scopes.remotePath)).to.not.throw();
+      expect(() => helper.command.catObject(mainSnap, false, helper.scopes.remotePath)).to.not.throw();
+    });
+
+    it('bit log should work without errors', () => {
+      expect(() => helper.command.logParsed('comp1')).to.not.throw();
+    });
+  });
+});
diff --git a/scopes/component/snap-distance/traverse-versions.ts b/scopes/component/snap-distance/traverse-versions.ts
index 5f6f5465f02e..18363cd884aa 100644
--- a/scopes/component/snap-distance/traverse-versions.ts
+++ b/scopes/component/snap-distance/traverse-versions.ts
@@ -245,12 +245,11 @@ export async function getAllVersionParents({
     const missingParents = allParentsFromObj.filter((parent) => !versionParents.some((v) => v.hash.isEqual(parent)));
     if (missingParents.length) {
       if (missingRefsFromVersionHistory) {
-        // stops the recursion
-        throw new Error(`unable to get the full history of "${modelComponent.id()}".
-the client sent the following snaps: ${versionParentsFromObjects.map((v) => v.hash.toString()).join(', ')}.
-however some of the parents of these snaps are missing from the local scope.
-missing snaps: ${missingParents.map((m) => m.toString()).join(', ')}
-`);
+        // Lean-lane-scope mode: missing parents are expected — they live on each component's
+        // home scope (e.g. main snaps for a lane that's far behind main). The lane scope no
+        // longer pulls them in. Return what we have; consumers will fetch from origin scopes
+        // when they need older history.
+        return versionParents;
       }
       // the VersionObject is not up to date.
       // recursively run this function and try to add these missing parents as heads so then it tries
diff --git a/scopes/scope/export/export.main.runtime.ts b/scopes/scope/export/export.main.runtime.ts
index e4011b21a3b8..7ec34b185345 100644
--- a/scopes/scope/export/export.main.runtime.ts
+++ b/scopes/scope/export/export.main.runtime.ts
@@ -33,7 +33,7 @@ import type { DependencyResolverMain } from '@teambit/dependency-resolver';
 import { DependencyResolverAspect } from '@teambit/dependency-resolver';
 import { persistRemotes, validateRemotes, removePendingDirs } from './export-scope-components';
 import { writeLastExport } from './last-export';
-import type { Lane, ModelComponent, ObjectItem, LaneReadmeComponent, BitObject, Ref } from '@teambit/objects';
+import type { Lane, ModelComponent, ObjectItem, LaneReadmeComponent, BitObject, Ref, Version } from '@teambit/objects';
 import { ObjectList } from '@teambit/objects';
 import { Scope, PersistFailed } from '@teambit/legacy.scope';
 import { getAllVersionHashes } from '@teambit/component.snap-distance';
@@ -512,7 +512,47 @@ if the scope name is wrong and you've already snapped/tagged, run "bit reset" to
         objectList.addIfNotExist(allObjectsData);
       };
 
-      const refsToExportPerComponent = await getRefsToExportPerComp();
+      const filterOutForeignMainOriginRefs = async (
+        refsPerComp: { modelComponent: ModelComponent; refs: Ref[] }[]
+      ): Promise<{ modelComponent: ModelComponent; refs: Ref[] }[]> => {
+        // when exporting a lane, drop refs that represent main-origin snaps belonging to
+        // components whose home scope is different from the lane's scope. those snaps already
+        // live on the component's home scope; pushing them to the lane scope is duplication
+        // (and the main driver of OOM when a lane is far behind main).
+        if (!lane) return refsPerComp;
+        const filtered = await mapSeries(refsPerComp, async ({ modelComponent, refs }) => {
+          const droppedRefs: string[] = [];
+          const keptRefs: Ref[] = [];
+          for (const ref of refs) {
+            const obj = await ref.load(scope.objects);
+            if (!obj || obj.getType() !== 'Version') {
+              keptRefs.push(ref);
+              continue;
+            }
+            const version = obj as Version;
+            const isLaneOrigin = Boolean(version.origin?.lane);
+            const isLocallyMutated = Boolean(version.squashed) || Boolean(version.unrelated);
+            const originScope = version.origin?.id?.scope;
+            const isForeignComponentScope = Boolean(originScope) && originScope !== remoteNameStr;
+            if (!isLaneOrigin && isForeignComponentScope && !isLocallyMutated) {
+              droppedRefs.push(ref.toString());
+              continue;
+            }
+            keptRefs.push(ref);
+          }
+          if (droppedRefs.length) {
+            this.logger.debug(
+              `export-scope-components, skipping ${droppedRefs.length} main-origin refs for ${modelComponent
+                .id()
+                .toString()} (already on component home scope, not the lane scope)`
+            );
+          }
+          return keptRefs.length ? { modelComponent, refs: keptRefs } : null;
+        });
+        return compact(filtered);
+      };
+
+      const refsToExportPerComponent = await filterOutForeignMainOriginRefs(await getRefsToExportPerComp());
       // don't use Promise.all, otherwise, it'll throw "JavaScript heap out of memory" on a large set of data
       await mapSeries(refsToExportPerComponent, processModelComponent);
       if (lane) {
diff --git a/scopes/scope/objects/models/model-component.ts b/scopes/scope/objects/models/model-component.ts
index 47df32eb6224..da20497544d4 100644
--- a/scopes/scope/objects/models/model-component.ts
+++ b/scopes/scope/objects/models/model-component.ts
@@ -562,6 +562,26 @@ export default class Component extends BitObject {
           }
         );
         versionsInfo = await getAllVersionsInfo({ modelComponent: this, repo, throws: false, startFrom });
+        // Lean-lane-scope fallback: if the lane is on a different scope from the component's
+        // home scope (e.g. a feature lane for a component that lives on main in another scope),
+        // older main snaps may not be on the lane scope. Re-fetch without lane so the fetcher
+        // routes to the component's home scope and brings in the missing main history.
+        if (
+          lane &&
+          lane.scope !== this.scope &&
+          versionsInfo.some((v) => v.error && errorIsTypeOfMissingObject(v.error))
+        ) {
+          await scope.scopeImporter.importWithoutDeps(
+            ComponentIdList.fromArray([this.toComponentId()]).toVersionLatest(),
+            {
+              cache: false,
+              includeVersionHistory: true,
+              collectParents: true,
+              reason: 'to collect logs from component home scope (lean-lane-scope fallback)',
+            }
+          );
+          versionsInfo = await getAllVersionsInfo({ modelComponent: this, repo, throws: false, startFrom });
+        }
       } catch (err) {
         logger.error(`collectLogs failed to import ${this.id()} history`, err);
       }
diff --git a/scopes/scope/remote-actions/export-validate.ts b/scopes/scope/remote-actions/export-validate.ts
index f04031a02931..bdca71572ee8 100644
--- a/scopes/scope/remote-actions/export-validate.ts
+++ b/scopes/scope/remote-actions/export-validate.ts
@@ -7,7 +7,6 @@ import { mergeObjects } from '@teambit/export';
 import type { Action } from './action';
 import { logger } from '@teambit/legacy.logger';
 import type { BitObjectList } from '@teambit/objects';
-import { getAllVersionHashes } from '@teambit/component.snap-distance';
 
 type Options = { clientId: string; isResumingExport: boolean };
 const NUM_OF_RETRIES = 60;
@@ -51,12 +50,15 @@ export class ExportValidate implements Action<Options> {
     const modelComponents = bitObjectList.getComponents();
     const externalComponents = modelComponents.filter((comp) => comp.scope !== this.scope.name);
     if (!externalComponents.length) return;
-    await this.scope.scopeImporter.importMissingVersionHistory(externalComponents);
-    // this will throw in case the history is missing
-    await Promise.all(
-      externalComponents.map((modelComponent) =>
-        getAllVersionHashes({ modelComponent, repo: this.scope.objects, throws: true })
-      )
+    // Lean-lane-scope: do NOT import full version-history into the lane scope. The history
+    // lives on each component's home scope (e.g. main snaps in component-scope, lane-b snaps in
+    // scope-b). Pulling them into the lane scope was the main source of fat-lane-scope OOM when
+    // a lane is far behind main. Consumers walking history will resolve missing parents by
+    // fetching from origin scopes on demand. We also skip the strict getAllVersionHashes check
+    // for the same reason — incomplete history on the lane scope is now expected.
+    logger.debug(
+      `export-validate, skipping importMissingVersionHistory for ${externalComponents.length} external components ` +
+        `(lean lane scope mode — their history stays on origin scopes)`
     );
   }