java.io.FileNotFoundException: File 'C:\Users\Conor\AppData\Roaming\.minecraft\assets\indexes\1.7.3.json' does not exist
    at org.apache.commons.io.FileUtils.openInputStream(FileUtils.java:299) ~[launcher.jar:?]
    at org.apache.commons.io.FileUtils.readFileToString(FileUtils.java:1711) ~[launcher.jar:?]
    at net.minecraft.launcher.Launcher.cleanupOrphanedAssets(Launcher.java:252) ~[launcher.jar:?]
    at net.minecraft.launcher.Launcher.performCleanups(Launcher.java:494) ~[launcher.jar:?]
    at net.minecraft.launcher.game.MinecraftGameRunner.launchGame(MinecraftGameRunner.java:221) ~[launcher.jar:?]
    at com.mojang.launcher.game.runner.AbstractGameRunner.onDownloadJobFinished(AbstractGameRunner.java:185) [launcher.jar:?]
    at com.mojang.launcher.updater.download.DownloadJob.popAndDownload(DownloadJob.java:122) [launcher.jar:?]
    at com.mojang.launcher.updater.download.DownloadJob.access$000(DownloadJob.java:12) [launcher.jar:?]
    at com.mojang.launcher.updater.download.DownloadJob$1.run(DownloadJob.java:86) [launcher.jar:?]
    at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.7.0_67]
    at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.7.0_67]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [?:1.7.0_67]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [?:1.7.0_67]
    at java.lang.Thread.run(Unknown Source) [?:1.7.0_67]