Fix ERROR_DS_USER_BUFFER_TO_SMALL (0X00002075) Fast

Cause #1: Your LDAP Query Asks for Too Much at Once

This is the one I see most often. Some app or script fires off an LDAP query that tries to grab too many attributes or too many objects in one shot. The buffer on the server side—usually 64KB by default on older Windows Server versions—can't hold it all, and you get 0X00002075.

A client last month had a backup tool that queried all user attributes on a domain with 10,000 users. The tool didn't page the results. Boom, error every 15 minutes. The fix was simple: tell the app to use paging. Most LDAP libraries support this natively. For PowerShell scripts, you add the -ResultPageSize parameter like so:

Get-ADUser -Filter * -Properties * -ResultPageSize 500

If you're using raw LDAP in C# or Python, set the LDAP control OID 1.2.840.113556.1.4.319 (page size control). That tells the server to split the response into chunks. Without it, the server tries to shove everything into one buffer.

Also check the query itself. Are you asking for cn, sn, givenName, mail, department, title, manager, directReports, thumbnailPhoto? That's a lot. Pull only the attributes you actually need. I had a developer who included tokenGroups by accident—that attribute alone can blow up a buffer because it contains nested group SIDs.

Cause #2: The Global Catalog Server Is Not Set or Is Overloaded

If the LDAP query targets a Global Catalog (GC) port—3268 or 3269—and the GC server either isn't available or is overwhelmed, you'll get this buffer error. The GC has its own size limit (5000 objects by default). When you exceed that without paging, the server doesn't give you a partial result—it throws 0X00002075.

I've seen this happen when someone points a management tool to a GC that's also a heavily used domain controller. The GC can't handle the load and the buffer overflows. Test by running this command:

nltest /dsgetdc:yourdomain.com /gc

It should return a valid GC server name. If it doesn't, you need to enable the Global Catalog on at least one domain controller. Open Active Directory Sites and Services, go to NTDS Settings on a DC, right-click, Properties, and check the box for Global Catalog. Reboot the DC after.

If the GC is there but the error persists, check the event logs for NTDS ISAM warnings. Had a case where a GC's database was nearly full—the buffer couldn't expand. Ran a database compaction with ntdsutil and the error went away.

Cause #3: A Corrupted Attribute in the User Object

This one's rarer but nasty. Sometimes a specific attribute on a user object gets corrupted—usually a multi-valued attribute like proxyAddresses or memberOf. When LDAP tries to read it, the buffer calculation goes wrong and you get 0X00002075.

I tracked this down once for a client where a single user had a proxyAddresses value that was 40KB long—someone copy-pasted a huge list of email addresses into it. The buffer couldn't hold it. To find and fix these, use this LDAP filter to search for oversized attributes:

Get-ADObject -Filter {ObjectClass -eq 'user'} -Properties * | Where-Object {$_.proxyAddresses.Count -gt 100}

If you find a culprit, remove the corrupt value with ADSI Edit. Go to the user object, open the attribute editor, clear out the bad entry. Re-run your query—should work now.

Another scenario: a third-party app wrote a binary attribute (like userParameters) incorrectly. Use repadmin /showobjmeta to see which DC last modified it and check if the attribute length is normal. If it's massive, delete and recreate the user.

Quick-Reference Summary Table

That's it. Three real causes, three real fixes. If you're still stuck after trying these, you might be dealing with a deeper schema issue. But 9 times out of 10, it's one of these three. Don't waste time rebuilding DCs—start with the query.