Known Issues So Far in SQL Server 2025
Whenever a brand spankin’ new version of any software comes out, there are bugs, and SQL Server is no exception. This has led to a mentality where folks don’t wanna install a new version of SQL Server until the first couple of Cumulative Updates come out, hopefully fixing the first big round of bugs.
So… are there bugs this time around?
Microsoft maintains a list of SQL Server 2025 known issues, and honestly, they’re not bad! There’s stuff in here that would have sucked to be the person to learn for the first time, but no showstoppers as far as I’m concerned. Some of the highlights:
On readable secondaries, you can get access violations if you enable Query Store without disabling PSPO. The fix is to disable PSPO.
Auditing events don’t write to the security log. The workaround is to write to a file instead, or like I’ve always told clients, if you need your auditing to be legally defensible, you need to use a third party appliance that sits in between SQL Server and the rest of the network, capturing all network packets.
Full text search won’t index all of big plaintext documents whose size is larger than 25MB. The workaround is to edit the registry to remove the 25MB limit.
It won’t install without TLS 1.2. I’ve had a couple of clients whose sysadmins had a little too much time on their hands, and insisted on turning off TLS 1.2 everywhere because “it’s deprecated.” For now, the fix is… re-enable TLS 1.2, do the install, and then turn it back off again.
It won’t install if you have >64 cores per CPU. This has been a problem with 2022 as well, and I’m simplifying that for the sake of the headline: the technical details are a little more complicated. The most common fix I’ve seen is to use virtualization, and configure the VM’s socket/cores setup so that you have more sockets, but less cores per socket.
PowerShell doesn’t work if you enforce strict encryption. The fix: turn off strict encryption. I find this amusing because the kinds of proactive people who use PowerShell are also the kinds of proactive people who would enforce strict encryption.
SQL auth logins are slower, although you probably won’t notice this unless you’re not using connection pooling and you’re tracking login times at scale, as Aaron Bertrand notes.
There are others in the full list, and surely there are more that are currently being investigated and haven’t been fully solved/documented yet, but overall – you know what, this isn’t bad! Knock on wood, this is shaping up to be one of the better, more reliable releases so far. Have you hit any bugs that aren’t in the list above? Let your fellow readers know in the comments.
16 Comments. Leave new
Not really a bug but will cause headaches, SQLNCLI for Linked Servers has been deprecated/ripped out in SQL 2025. The driver replacing SQLNCLI is MSOLEDBSQL. So no more easy SQL pass through using linked servers for SQL Logins that are not sysadmins. You now have 3 options:
1. Use a sysadmin login
2. Use Keberos / Windows authentication
3. A stored procedure with EXECUTE AS OWNER (still looking into this one, it was recommended by ChatGPT)
Yeah, I didn’t list that as a known issue because it’s not really a “bug” with 2025 – it’s by design. I remember it being deprecated in 2022, and this is a surprising case of Microsoft actually making good on a deprecation! Usually they let deprecated stuff soldier on for several releases – they’re really polite about that.
Thanks, that might be a showstopper. We use SQL logins a lot.
Yikes, good to know, thank you Tim Grant.
I’m hoping that you could elaborate on the problem you are describing. We had switched to MSOLEDBSQL19 for our linked SQL servers in server 2019, and didn’t have any issues mapping SQL server logins, but I *am* having an odd issue with this in 2025.
Not recommended but you can install the SQLNCLI in your SQL Server 2025. you must download the last stable version, which is the SQL Server 2012 Native Client (v11).
I presume you can install on less than 64 cores , then reconfigure to more?
Joe – it’s Christmas morning here in Shanghai, so I’m feeling particularly generous, so I’m not going to type out a nasty, passive-aggressive reply about how you didn’t take the time to click on the link explaining the issue, where it clearly states in big, highlighted text, “the Database Engine doesn’t start if it detects more than 64 logical cores per NUMA node.” It’s the season for cheer and giving, so I’m going to take an alternate approach.
Instead, I’m going to raise a cup of alcohol-infused coffee, wish you and yours the happiest of holidays. Cheers!
Full-text indexes need to be rebuilt on SQL 2025, which is quite a significant breaking change if you have a large volume of full-text indexes. Or there is a poorly documented workaround to continue to use your old indexes.
It gets a bit worse, though. I have an open case with MS support where rebuilding full-text indexes causes the SQL instance to crash with a memory dump. I’m sure MS support will get to the bottom of the issue and patch it in a future CU. I would avoid SQL 2025 for now if you have a lot of full-text data – or at least do a lot of testing for your workloads. I wasn’t aware of the 25MB limit – maybe it’s related.
Interesting! What happens if the indexes aren’t rebuilt? (I’m not in a position to run this test quickly.)
If you do nothing, your full-text queries will fail with an error. To keep using version 1 you need to run:
ALTER DATABASE SCOPED CONFIGURATION
SET FULLTEXT_INDEX_VERSION = 1;
Which is fine, but you also need to do this:
“You must then copy the legacy word breaker and filter binaries from an older instance to the target instance’s binn folder.”
Having to copy files from an older version isn’t great. The instructions could also be improved to make it clear which files need to be copied.
Jeez, that’s crazy! I had no idea. Have you seen any official documentation on this?
https://learn.microsoft.com/en-us/sql/database-engine/breaking-changes-to-database-engine-features-in-sql-server-2025?view=sql-server-ver17#full-text-queries-and-populations-fail-after-upgrade
I suspect it might catch a few people out.
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