diff --git a/Xcodes/Backend/AppState+Update.swift b/Xcodes/Backend/AppState+Update.swift
index 48d9c21..660d2f0 100644
--- a/Xcodes/Backend/AppState+Update.swift
+++ b/Xcodes/Backend/AppState+Update.swift
@@ -200,6 +200,31 @@ extension AppState {
                 }
                 return xcodes
             }
+            .map(filterPrereleasesThatMatchReleaseBuildMetadataIdentifiers)
             .eraseToAnyPublisher()
     }
+    
+    /// Xcode Releases may have multiple releases with the same build metadata when a build doesn't change between candidate and final releases.
+    /// For example, 12.3 RC and 12.3 are both build 12C33
+    /// We don't care about that difference, so only keep the final release (GM or Release, in XCModel terms).
+    /// The downside of this is that a user could technically have both releases installed, and so they won't both be shown in the list, but I think most users wouldn't do this.
+    func filterPrereleasesThatMatchReleaseBuildMetadataIdentifiers(_ availableXcodes: [AvailableXcode]) -> [AvailableXcode] {
+        var filteredAvailableXcodes: [AvailableXcode] = []
+        for availableXcode in availableXcodes {
+            if availableXcode.version.buildMetadataIdentifiers.isEmpty {
+                filteredAvailableXcodes.append(availableXcode)
+                continue
+            }
+            
+            let availableXcodesWithSameBuildMetadataIdentifiers = availableXcodes
+                .filter({ $0.version.buildMetadataIdentifiers == availableXcode.version.buildMetadataIdentifiers })
+            if availableXcodesWithSameBuildMetadataIdentifiers.count > 1,
+               availableXcode.version.prereleaseIdentifiers.isEmpty || availableXcode.version.prereleaseIdentifiers == ["GM"] {
+                filteredAvailableXcodes.append(availableXcode)
+            } else if availableXcodesWithSameBuildMetadataIdentifiers.count == 1 {
+                filteredAvailableXcodes.append(availableXcode)
+            }
+        }
+        return filteredAvailableXcodes
+    } 
 }
diff --git a/XcodesTests/AppStateUpdateTests.swift b/XcodesTests/AppStateUpdateTests.swift
index a640c90..b0c668c 100644
--- a/XcodesTests/AppStateUpdateTests.swift
+++ b/XcodesTests/AppStateUpdateTests.swift
@@ -106,4 +106,14 @@ class AppStateUpdateTests: XCTestCase {
         
         XCTAssertEqual(subject.allXcodes.map(\.version), [Version("1.2.3")!, Version("0.0.0+ABC123")!]) 
     }
+    
+    func testFilterReleasesThatMatchPrereleases() {
+        let result = subject.filterPrereleasesThatMatchReleaseBuildMetadataIdentifiers(
+            [
+                AvailableXcode(version: Version("12.3.0+12C33")!, url: URL(string: "https://apple.com")!, filename: "Xcode_12.3.xip", releaseDate: nil),
+                AvailableXcode(version: Version("12.3.0-RC+12C33")!, url: URL(string: "https://apple.com")!, filename: "Xcode_12.3_RC_1.xip", releaseDate: nil),
+            ]
+        )
+        XCTAssertEqual(result.map(\.version), [Version("12.3.0+12C33")])
+    }
 }