If you've been spending your afternoon deep in Luau code, you might have run into a roblox isreadonly script error that just won't go away. It's honestly one of the most frustrating things because it usually happens right when you're trying to automate something or streamline your workflow. You go to change a property or edit a line of code, and the engine basically tells you "no."
It's not always obvious why it's happening, either. Sometimes it feels like Roblox is just being stubborn for no reason, but there's usually a very specific technical logic behind why a script or its properties are locked down. Let's break down what's actually happening when you see this and how you can get around it without pulling your hair out.
Why scripts become read-only in the first place
Most of the time, the "IsReadOnly" status is a safety feature. Roblox doesn't want you—or a malicious script—changing things that could break the game's core stability or security. If every script could be modified by any other script at any time while the game was running, it would be an absolute nightmare for developers.
One of the most common reasons you'll see a script marked as read-only is because of the LinkedSource feature. If your script is linked to a cloud asset rather than being stored purely inside the place file, Roblox locks the Source property. You can't just change the code via a command bar or another script because that code technically "lives" elsewhere. To change it, you'd have to edit the original asset, not the instance sitting in your workspace.
Another big one is the context of the script. Scripts running in a live game environment have way more restrictions than scripts running in a plugin or in the Studio command bar. If you're trying to change the Source property of a script during a live session, you're going to hit a wall. Roblox explicitly forbids changing script code at runtime for security reasons—imagine if an exploiter could just rewrite your admin script on the fly!
The deal with the Script.Source property
I've seen a lot of people try to write plugins that generate code, only to get hit with an error saying the script is read-only. Here's the thing: while you can edit the Source of a script using a plugin or the command bar in Studio, there are still rules.
If you're trying to do this through a standard LocalScript or Script while the game is actually running (even in a "Play Solo" test), it's not going to work. The Source property is protected. It's accessible to the Studio API for plugin developers, but it's completely off-limits to the standard runtime engine.
If you're building a tool that needs to generate code, you have to make sure you're operating in a Plugin Security Level. If you aren't, the engine treats your attempt to write code as a major red flag and shuts it down. This is why you'll often see "isreadonly" popping up in the output window when you're experimenting with dynamic code generation.
Tables and the "frozen" state
Sometimes, when people talk about a roblox isreadonly script issue, they're actually talking about tables within their scripts. Luau introduced a feature called table.freeze(), which is incredibly useful but can be confusing if you forget you used it.
When you freeze a table, it becomes permanently read-only. If you try to add a new key or change a value, the script will throw an error. This is a great way to protect your configuration files or core game data from being accidentally messed with by other modules, but it's a "one-way trip." You can't "unfreeze" a table. If you need to change it, you have to clone the table, modify the clone, and then potentially freeze the new one.
It's easy to see how this gets mixed up with script-level read-only errors, especially if your module is returning a frozen table. You might think the script itself is the problem, but it's actually just the data structure you're trying to poke.
Dealing with LinkedSource headaches
If you're working on a large project with a team, you might be using LinkedSource. This was the old-school way of syncing code across different places in the same universe. When a script has a LinkedSource ID attached to it, the Source property becomes read-only in the Properties window and to any script trying to modify it.
Honestly, LinkedSource is a bit of a legacy feature at this point. Most people have moved over to Packages. Packages are much more robust, but they come with their own version of the read-only problem. If a script is part of a Package, you have to "Modify" the package before you can change the code. If you try to script a change to a package-protected script without checking it out first, you're going to run into that same "read-only" wall.
How to actually fix the error
So, how do you fix it? Well, it depends on what you're trying to do.
- If you're writing a plugin: Make sure you aren't trying to change a script's source while the game is in "Run" or "Play" mode. You should only be doing this while the Studio is in "Edit" mode.
- Check for Packages: If the script has a little link icon next to it in the Explorer, it's part of a package. Right-click it and see if you need to "Edit" or "Unbind" it.
- Check for LinkedSource: Look in the properties of the script. If there's a string in the
LinkedSourcebox, that's your culprit. Clearing that box will make the script editable again, but keep in mind you'll lose the link to the cloud-saved version. - Runtime Modifications: If you're trying to change code while the game is running just don't. Use
ModuleScriptsand logic gates instead. Instead of rewriting a script, have the script check a variable or aRemoteEventto change its behavior.
Is there a workaround for dynamic code?
People often ask if they can use loadstring() to get around read-only script limitations. While loadstring() lets you execute code from a string, it doesn't actually change the script it's running in. Plus, you have to manually enable loadstring in the ServerScriptService properties, and it's generally considered a bit of a security risk if you don't know exactly what you're doing.
If you find yourself constantly wishing you could edit a roblox isreadonly script at runtime, you might need to rethink your architecture. Usually, the "read-only" status is telling you that you're trying to do something the hard way. Using ModuleScripts that return functions or tables is almost always the better way to handle dynamic behavior.
Final thoughts on the "Read-Only" frustration
At the end of the day, seeing a "read-only" error is usually the engine's way of saying "Hold on, this isn't safe." Whether it's because of a cloud-linked script, a frozen table, or a security restriction, it's there to prevent your game from turning into a buggy mess.
If you're stuck, just take a step back and look at where the script is located and what properties it has. Nine times out of ten, it's just a package or a linked asset that needs to be toggled off. It's a minor annoyance once you know what to look for, but it definitely feels like a brick wall when you first hit it. Just keep an eye on your script properties and your Studio mode, and you should be able to bypass the "isreadonly" hurdle pretty easily.