diff --git a/.changeset/hot-lies-rescue.md b/.changeset/hot-lies-rescue.md
new file mode 100644
index 0000000000..60faff7bc3
--- /dev/null
+++ b/.changeset/hot-lies-rescue.md
@@ -0,0 +1,5 @@
+---
+"@pnpm/core": patch
+---
+
+When the lockfile is not up to date make it clear what `package.json` is out of sync.
diff --git a/pkg-manager/core/src/install/index.ts b/pkg-manager/core/src/install/index.ts
index a290415ef4..5583559ff3 100644
--- a/pkg-manager/core/src/install/index.ts
+++ b/pkg-manager/core/src/install/index.ts
@@ -441,7 +441,7 @@ Note that in CI environments, this setting is enabled by default.`,
 
             throw new PnpmError('OUTDATED_LOCKFILE',
               `Cannot install with "frozen-lockfile" because ${WANTED_LOCKFILE} is not up to date with ` +
-              path.relative(opts.lockfileDir, path.join(rootDir, 'package.json')), {
+              path.join('<ROOT>', path.relative(opts.lockfileDir, path.join(rootDir, 'package.json'))), {
                 hint: `Note that in CI environments this setting is true by default. If you still need to run install in such cases, use "pnpm install --no-frozen-lockfile"
 
     Failure reason:
diff --git a/pkg-manager/core/test/install/frozenLockfile.ts b/pkg-manager/core/test/install/frozenLockfile.ts
index 7822d95c03..7691de8ec0 100644
--- a/pkg-manager/core/test/install/frozenLockfile.ts
+++ b/pkg-manager/core/test/install/frozenLockfile.ts
@@ -28,7 +28,7 @@ test(`frozen-lockfile: installation fails if specs in package.json don't match t
         'is-positive': '^3.1.0',
       },
     }, testDefaults({ frozenLockfile: true }))
-  ).rejects.toThrow(`Cannot install with "frozen-lockfile" because ${WANTED_LOCKFILE} is not up to date with package.json`)
+  ).rejects.toThrow(`Cannot install with "frozen-lockfile" because ${WANTED_LOCKFILE} is not up to date with ${path.join('<ROOT>', 'package.json')}`)
 })
 
 test(`frozen-lockfile+hoistPattern: installation fails if specs in package.json don't match the ones in ${WANTED_LOCKFILE}`, async () => {
@@ -46,7 +46,7 @@ test(`frozen-lockfile+hoistPattern: installation fails if specs in package.json
         'is-positive': '^3.1.0',
       },
     }, testDefaults({ frozenLockfile: true, hoistPattern: '*' }))
-  ).rejects.toThrow(`Cannot install with "frozen-lockfile" because ${WANTED_LOCKFILE} is not up to date with package.json`)
+  ).rejects.toThrow(`Cannot install with "frozen-lockfile" because ${WANTED_LOCKFILE} is not up to date with ${path.join('<ROOT>', 'package.json')}`)
 })
 
 test(`frozen-lockfile: fail on a shared ${WANTED_LOCKFILE} that does not satisfy one of the package.json files`, async () => {
@@ -97,7 +97,7 @@ test(`frozen-lockfile: fail on a shared ${WANTED_LOCKFILE} that does not satisfy
 
   await expect(
     mutateModules(projects, testDefaults({ frozenLockfile: true, allProjects: [project1, project2] }))
-  ).rejects.toThrow(`Cannot install with "frozen-lockfile" because ${WANTED_LOCKFILE} is not up to date with p1${path.sep}package.json`)
+  ).rejects.toThrow(`Cannot install with "frozen-lockfile" because ${WANTED_LOCKFILE} is not up to date with ${path.join('<ROOT>', 'p1/package.json')}`)
 })
 
 test(`frozen-lockfile: should successfully install when ${WANTED_LOCKFILE} is available`, async () => {