macOS Updated March 2026 8 min read

Alin Marin · CEO Radical Service · January 2026

Over 12 years of experience in Apple repairs · 25,000+ devices repaired · ASE Bucharest

macOS Tahoe 26 — Known Bugs and How to Fix Them

Your Mac is having issues after the macOS Tahoe 26 update? Wi-Fi drops, Mac freezes, battery drains fast. A complete guide with step-by-step fixes, tested in Radical's workshop.

100+

reported bugs

26.3

current version

48h

avg. normalisation time

bugs covered

⚠

Before any fix

Back up with Time Machine or an external disk. Apple menu → System Settings → General → Time Machine. If something goes wrong during a fix, you have somewhere to roll back to. Most of the issues below are software — not hardware — and resolve without a service visit.

Critical

Unstable Wi-Fi and frequent disconnects

Symptom

Frequent disconnects, random IP changes, download speeds cut in half. Appears mostly on MacBook Air M3 and iMac 24-inch.

Cause

Bug in the Wi-Fi 6E driver that doesn't correctly handle legacy routers. Conflict between the 6GHz band and older 5GHz networks.

How to fix

1 Click the Wi-Fi icon → "Wi-Fi Settings" → find the problematic network → gear icon → "Forget This Network"
2 Reconnect with the password. If the issue returns: open Terminal and run the commands below
3 System Settings → Network → VPN & Filters → temporarily disable DNS filtering
4 Restart the Mac

Terminal

sudo dscacheutil -flushcache
sudo killall -HUP mDNSResponder

Status: Fix confirmed in macOS 26.1+. Install update from System Settings → General → Software Update.

Medium

Windows can't be resized (Liquid Glass corners)

Symptom

The new Liquid Glass windows have such rounded corners that the resize area has become almost impossible to grab — just 3px vs 8px in Sonoma.

Cause

Corner radius increased from 12px to 28px in the new design. The clickable resize area shrank drastically.

How to fix

1 Resize from the side or top edges (not the corner)
2 Or: System Settings → Desktop & Dock → enable "Stage Manager" — windows become normally resizable
3 Alternatively: install Rectangle (free, open-source) — it offers resize hotkeys (Option + Cmd + R)

Status: Apple confirmed it as a known issue. Fix expected in macOS 26.4.

Critical

Mac restarts itself (Kernel Panic)

Symptom

Spontaneous restart with no warning, grey screen followed by automatic restart. Logs show kernel panic in the Time Machine module.

Cause

Bug in the Time Machine integration with the new filesystem layer in Tahoe 26.3.

How to fix

1 System Settings → General → Time Machine → Toggle OFF
2 Wait 15 minutes — check if crashes stop
3 If you have an external volume mounted: Terminal → diskutil list → diskutil unmount /Volumes/[DriveName]
4 If the problem persists: full backup + clean reinstall (Recovery Mode: Cmd+R at startup)

Terminal

diskutil list
diskutil unmount /Volumes/BackupDrive

Status: Urgent update to 26.3.1+ when available. Disable auto-backup until then.

Critical

Battery drains rapidly (40-60% more than Sonoma)

Symptom

Battery life from 15 hours to 8–9 hours. Activity Monitor shows kernel_task at 50%+ CPU. Mac warms up even at rest.

Cause

Spotlight reindexing in the first 24–48h, aggressive iCloud sync, Apple Intelligence running in background.

How to fix

1 System Settings → Siri & Spotlight → deselect indexing for unnecessary folders
2 System Settings → [Account] → iCloud → temporarily disable Photos, Files, Mail (24–48h)
3 System Settings → General → Login Items → remove unnecessary apps
4 System Settings → Apple Intelligence → disable if you don't actively use it
5 Open Activity Monitor → Energy tab → sort by "CPU Time" → identify the culprit processes

Terminal

top -o %CPU -o %MEM

Status: Normal in the first 24–48h post-update. If it persists after 48h with Spotlight and iCloud disabled, it's a real bug — update to the latest version.

Medium

Apple Mail and Calendar freeze or won't sync

Symptom

Mail and Calendar close abruptly. Sync with iCloud Calendar fails or events stop appearing.

Cause

Bug in the SQLite database layer in macOS Tahoe — corruption in the local cache.

How to fix

1 System Settings → Mail → Accounts → delete the affected account → add it back
2 Or reset the Mail cache from Terminal with the commands below
3 Restart the Mac after the reset

Terminal

rm ~/Library/Mail\ Downloads/*
rm ~/Library/Mail\ Index/V*/*
killall Mail

Status: If the problem returns: disable iCloud Mail sync for 24h, then re-enable.

Medium

Spotlight can't find files

Symptom

Cmd+Space no longer finds documents even though they exist on the Mac. Results are incomplete or missing.

Cause

Incomplete or corrupted Spotlight index after the update.

How to fix

1 System Settings → Siri & Spotlight → Privacy → add the main drive to exclusions → wait 10 sec → remove it
2 Spotlight will fully reindex (30–60 minutes depending on disk size)
3 Or force full reindexing from Terminal with the commands below

Terminal

sudo mdutil -i off /
sudo mdutil -i on /

Status: Reindexing resolves the issue permanently. No system update needed.

Critical

Bluetooth — AirPods, mouse, keyboard disconnects

Symptom

Bluetooth devices disconnect randomly and don't reconnect automatically. AirPods disconnect when switching activity.

Cause

Bug in the Bluetooth daemon in Tahoe that doesn't handle automatic reconnect properly.

How to fix

1 System Settings → Bluetooth → click gear next to device → "Remove" → confirm
2 Restart Mac
3 Re-pair the device (put it in pairing mode)
4 If the issue returns: reset the Bluetooth module from Terminal with the commands below

Terminal

sudo launchctl stop com.apple.bluetoothd
sleep 2
sudo launchctl start com.apple.bluetoothd

Status: Partially fixed in 26.2. If it persists after update, try SMC reset (hold Power 10 sec).

Medium

GPU thermal throttling on Apple Silicon

Symptom

M3 and M4 Macs overheat and performance drops sharply under load. Reported temperatures of 95–100°C.

Cause

The thermal driver in Tahoe doesn't correctly calibrate power limits for Apple Silicon chips.

How to fix

1 Download iStat Menus (free trial) for real-time temperature monitoring
2 Normal: 50–75°C · Alert: 90°C+ · Throttling: 100°C
3 System Settings → General → About → disable "Low Power Mode" (paradoxically, can worsen throttling)
4 Disconnect external monitors temporarily if possible
5 Clean ventilation slots with compressed air

Status: Fix in progress at Apple. Monitor temperature and avoid prolonged intensive workloads.

Critical

Kernel panic when launching certain apps (Adobe, Office, Final Cut)

Symptom

Apps such as Adobe Photoshop, Microsoft Office or Final Cut Pro trigger kernel panic on launch.

Cause

Incompatibility with new security features in Tahoe (changes in System Integrity Protection).

How to fix

1 Check on the developer's website that the app is compatible with macOS 26
2 Reinstall the app (fresh download, not from backup)
3 If that doesn't help: boot in Recovery Mode (Cmd+R) → Utilities → Terminal → csrutil disable → restart
4 Test the app — then MANDATORY: re-enable SIP: csrutil enable

Terminal

# IN RECOVERY MODE:
csrutil disable
# after testing, re-enable:
csrutil enable

Status: ⚠ Disabling SIP is a security risk. Enable immediately after testing. Wait for a compatibility update from the developer.

Activity Monitor — high CPU usage after the macOS Tahoe update

Recommended settings after the update

✗ Disable

→ Transparency effects (Accessibility)
→ Fullscreen animations
→ Auto-brightness (if it drains the battery)
→ Spotlight indexing for large folders
→ Apple Intelligence (if you don't use it)

✓ Enable

→ Firewall (Network & Security)
→ FileVault encryption
→ Automatic updates (26.x patches)
→ Regular Time Machine backup
→ Low Power Mode if you have battery issues

Rollback procedure (if nothing works)

If Tahoe is unstable and you can't wait for Apple's fixes, you can roll back to Sonoma. Takes 30–90 minutes.

1 Full backup on external disk or Time Machine
2 Boot into Recovery Mode: Cmd + R at startup
3 Disk Utility → Erase → select the main disk
4 Reinstall macOS (Sonoma if available in Recovery)
5 Restore from Time Machine after install

When to bring it in for service

If after all the fixes above the issue persists, it's probably hardware:

→

Unstable Wi-Fi after SMC reset and NVRAM reset

Defective Wi-Fi antenna or burned Wi-Fi chip — ~600-900 RON repair

→

Battery drains fast even in Safe Mode

Battery degraded — needs replacement (~400 RON)

→

System laggy after repeated resets and updates

Defective SSD or burned logic — free diagnostic at our shop

→

Kernel panic on any app, including Apple's own

Possible corrupted RAM or logic issue — diagnostic needed

Don't replace a MacBook battery yourself — Apple MacBooks are glued and the risk of internal damage is high.

Frequently asked questions

Why is Wi-Fi unstable after the macOS Tahoe update?

macOS Tahoe has a known bug in the Wi-Fi 6E driver that creates conflicts with older routers. Main fix: forget the Wi-Fi network and reconnect. DNS flush from Terminal solves more persistent cases. Apple released patches in versions 26.1+.

My Mac restarts itself after the Tahoe 26.3 update — what do I do?

Disable Time Machine temporarily (System Settings → General → Time Machine → Toggle OFF) and check if crashes stop. The 26.3 bug is specific to the Time Machine module. If you have an external volume mounted, unmount it. Update to 26.3.1+ when available is mandatory.

MacBook battery drains faster after Tahoe — is it normal?

Yes, in the first 24–48h it's normal — Spotlight reindexes the entire disk and iCloud syncs aggressively. If after 48h with Spotlight and Apple Intelligence disabled the battery is still poor, it's a real bug. Check Activity Monitor → Energy and identify the culprit process. Update to the current version is recommended.

Should I update to macOS Tahoe 26.3?

Yes — the update to 26.3 is urgent for security reasons. It fixes a critical exploit in the dyld dynamic linker that allowed malicious code execution. The downsides (the bugs above) are acceptable vs. the security risk. Install as soon as possible.

Windows can't be resized after Tahoe — is there a quick fix?

The Liquid Glass redesign reduced the corner resize area to just 3px. Quick solution: enable Stage Manager (System Settings → Desktop & Dock) which restores normal window behaviour. Alternatively, install Rectangle (free) for full control via hotkeys. Apple confirmed the fix comes in 26.4.

⚠️

macOS Tahoe 26.4 bricks MacBook M2/M3 — critical firmware bug

Your Mac won't turn on at all after the update? DFU Revive fails with error 4013? Find out how we repair the firmware in 24h, 600 RON VAT included.

Still having issues after Tahoe?

We provide professional diagnostic — both hardware and software. If it's software, we reinstall macOS. If it's hardware, we repair or replace the defective components. Free diagnostic in Bucharest. English-speaking technicians.

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