diff --git a/internal/getproviders/filesystem_mirror_source_test.go b/internal/getproviders/filesystem_mirror_source_test.go
index 6d66dd29b..24ecd595f 100644
--- a/internal/getproviders/filesystem_mirror_source_test.go
+++ b/internal/getproviders/filesystem_mirror_source_test.go
@@ -92,6 +92,16 @@ func TestFilesystemMirrorSourceAllAvailablePackages(t *testing.T) {
 	}
 }
 
+// In this test the directory layout is invalid (missing the hostname
+// subdirectory). The provider installer should ignore the invalid directory.
+func TestFilesystemMirrorSourceAllAvailablePackages_invalid(t *testing.T) {
+	source := NewFilesystemMirrorSource("testdata/filesystem-mirror-invalid")
+	_, err := source.AllAvailablePackages()
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
 func TestFilesystemMirrorSourceAvailableVersions(t *testing.T) {
 	source := NewFilesystemMirrorSource("testdata/filesystem-mirror")
 	got, err := source.AvailableVersions(nullProvider)
diff --git a/internal/getproviders/filesystem_search.go b/internal/getproviders/filesystem_search.go
index 23a7d3ce7..e3cd047b1 100644
--- a/internal/getproviders/filesystem_search.go
+++ b/internal/getproviders/filesystem_search.go
@@ -52,6 +52,22 @@ func SearchLocalDirectory(baseDir string) (map[addrs.Provider]PackageMetaList, e
 		namespace := parts[1]
 		typeName := parts[2]
 
+		// validate each part
+		// The legacy provider namespace is a special case.
+		if namespace != addrs.LegacyProviderNamespace {
+			_, err = addrs.ParseProviderPart(namespace)
+			if err != nil {
+				log.Printf("[WARN] local provider path %q contains invalid namespace %q; ignoring", fullPath, namespace)
+				return nil
+			}
+		}
+
+		_, err = addrs.ParseProviderPart(typeName)
+		if err != nil {
+			log.Printf("[WARN] local provider path %q contains invalid type %q; ignoring", fullPath, typeName)
+			return nil
+		}
+
 		hostname, err := svchost.ForComparison(hostnameGiven)
 		if err != nil {
 			log.Printf("[WARN] local provider path %q contains invalid hostname %q; ignoring", fullPath, hostnameGiven)
diff --git a/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/2.0.0/darwin_amd64/terraform-provider-null b/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/2.0.0/darwin_amd64/terraform-provider-null
new file mode 100644
index 000000000..daa9e3509
--- /dev/null
+++ b/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/2.0.0/darwin_amd64/terraform-provider-null
@@ -0,0 +1 @@
+# This is just a placeholder file for discovery testing, not a real provider plugin.
diff --git a/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/2.0.0/linux_amd64/terraform-provider-null b/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/2.0.0/linux_amd64/terraform-provider-null
new file mode 100644
index 000000000..daa9e3509
--- /dev/null
+++ b/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/2.0.0/linux_amd64/terraform-provider-null
@@ -0,0 +1 @@
+# This is just a placeholder file for discovery testing, not a real provider plugin.
diff --git a/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/invalid b/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/invalid
new file mode 100644
index 000000000..289663a2a
--- /dev/null
+++ b/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/invalid
@@ -0,0 +1 @@
+This should be ignored because it doesn't follow the provider package naming scheme.
diff --git a/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/terraform-provider-null_2.1.0_linux_amd64.zip b/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/terraform-provider-null_2.1.0_linux_amd64.zip
new file mode 100644
index 000000000..68a550271
--- /dev/null
+++ b/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/terraform-provider-null_2.1.0_linux_amd64.zip
@@ -0,0 +1,5 @@
+This is just a placeholder file for discovery testing, not a real provider package.
+
+This file is what we'd find for mirrors using the "packed" mirror layout,
+where the mirror maintainer can just download the packages from upstream and
+have Terraform unpack them automatically when installing.
diff --git a/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/terraform-provider-null_invalid.zip b/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/terraform-provider-null_invalid.zip
new file mode 100644
index 000000000..289663a2a
--- /dev/null
+++ b/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/terraform-provider-null_invalid.zip
@@ -0,0 +1 @@
+This should be ignored because it doesn't follow the provider package naming scheme.
diff --git a/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/terraform-provider-null_invalid_invalid_invalid.zip b/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/terraform-provider-null_invalid_invalid_invalid.zip
new file mode 100644
index 000000000..289663a2a
--- /dev/null
+++ b/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/null/terraform-provider-null_invalid_invalid_invalid.zip
@@ -0,0 +1 @@
+This should be ignored because it doesn't follow the provider package naming scheme.
diff --git a/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/random-beta/1.2.0/linux_amd64/terraform-provider-random-beta b/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/random-beta/1.2.0/linux_amd64/terraform-provider-random-beta
new file mode 100644
index 000000000..daa9e3509
--- /dev/null
+++ b/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/random-beta/1.2.0/linux_amd64/terraform-provider-random-beta
@@ -0,0 +1 @@
+# This is just a placeholder file for discovery testing, not a real provider plugin.
diff --git a/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/random/1.2.0/linux_amd64/terraform-provider-random b/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/random/1.2.0/linux_amd64/terraform-provider-random
new file mode 100644
index 000000000..daa9e3509
--- /dev/null
+++ b/internal/getproviders/testdata/filesystem-mirror-invalid/hashicorp/random/1.2.0/linux_amd64/terraform-provider-random
@@ -0,0 +1 @@
+# This is just a placeholder file for discovery testing, not a real provider plugin.